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144 Questions (108 slides Q&A) 54:30 timed Qs Unknown time for answers 158 slides Lecture ~6 hours Substrate Catalytic site Allosteric site Cofactor Apoenzyme Holoenzyme Metalloenzyme Zymogen Isozyme Enzyme without cofactor Enzyme with cofactor Sometimes called coenzyme One of several enzymes that catalyze the same reaction Aka: binding site Where the reaction takes place Site where substrates attach Site where effectors attach Aka: reactant Requires an ion for activity Inactive enzyme Endergonic or exergonic? Enzyme Marker Full name Tissue / Organ ALP Alkaline phosphatase Bone or liver ACP Acid phosphatase Prostate Amylase / lipase Pancreas AST / SGOT Aspartate aminotransferase Heart and liver ALT / SGPT Alanine aminotransferase Heart and liver LDH Lactate dehydrogenase Heart, liver and skeletal muscle CK / CPK Creatine (phospho) kinase Heart and skeletal muscle IUB Systematic Classification and nomenclature International Union of Biochemistry (IUB) Enzymes are classified into 6 classes according to function: 1. Oxidoreductase Re-dox reactions: A + B=O A=O + B 2. Transferase Transfer groups between substrates 3. Hydrolase Break substrates by addition of water 4. Lyase Break substrates without water 5. Isomerase Convert isomers: AB2 B—A—B 6. Ligase Ligate with new covalent bond: C—C, O, N, S Synthetase: uses ATP/GTP as energy source Synthase: uses other energy IUB Class Function Common name Cofactors 1. Oxidoreductase Re-dox reactions; moves hydrogen Dehydrogenase Catabolic: NAD and FAD Anabolic: NADP Hydroxylase Transfers –OH group Hydroxylase Vit C and Cu or Fe 2. Transferase Moves a functional Transferase group between two compounds Aminotransferase Swaps amino group for a ketone group Aminotransferase Vit B6 (pyridoxal phosphate) Kinase Transfers PO4 Kinase ATP and Mg2+ 3. Hydrolase Splits into 2 using H2O Substrate + ase -- 4. Lyase Splits into 2, no H2O Substrate + ase -- Removes or adds CO2 (De)carboxylase Biotin 5. Isomerase Rearrange molecule Isomerase -- 6. Ligase Joins to molecules Ligase, synthase or synthetase -- (De)carboxylase Enzymes and Coenzymes Use the following diagram to answer questions 1-6: (B) (A) (C) + 50 kcal NAD+ (D) NADH (E) ONE MINUTE To answer all 1. Which one is the product of the reaction 2. Which one is the reduced form of the coenzyme 3. Which one is the oxidized form of the coenzyme 4. Which is the substrate of the reaction 5. Is this reaction reversible or irreversible 6. Is this reaction endergonic or exergonic 45 sec to answer both 7. Pepsin, an enzyme produced in the stomach to digest proteins, belongs to which class of enzyme a. oxidoreductase b. transferase c. hydrolase d. lyase 8. To which class of enzyme does alcohol dehydrogenase belong: a. oxidoreductase b. transferase c. hydrolase d. lyase 45 sec to answer both 9. To which class of enzyme does acetyltransferase belong: a. oxidoreductase b. transferase c. hydrolase d. Lyase 10. To which class of enzyme does glutamine synthetase belong: ATP + L-glutamate + NH3 ADP + Pi + L-glutamine a. oxidoreductase b. transferase c. hydrolase d. ligase 1:30 to answer all three 11. The reason enzymes increase the rate of chemical reactions is because they a. increase the activation energy required b. lower the activation energy required c. increase the free energy of the compounds formed d. decrease the free energy of the compounds formed 12. a. b. c. d. What is true about Vmax it reflects the concentration of product in a sample it cannot be affected by the temperature of the reaction it cannot be affected by the pH of the reaction it cannot be affected by the substrate concentration 13. Patients who have bone diseases or hepatobiliary diseases would have a higher concentration of a. lactate dehydrogenase b. alkaline phosphatase c. creatine phosphokinase d. α-amylase Use the following diagram to answer questions 1-6: (B) (A) (C) + 50 kcal NAD+ (D) NADH (E) 1. Which one is the product of the reaction C 2. Which one is the reduced form of the coenzyme E 3. Which one is the oxidized form of the coenzyme D 4. Which is the substrate of the reaction A 5. Is this reaction reversible or irreversible Irreversible 6. Is this reaction endergonic or exergonic Exergonic 7. Pepsin, an enzyme produced in the stomach to digest proteins, belongs to which class of enzyme a. oxidoreductase b. transferase c. hydrolase d. lyase 8. To which class of enzyme does alcohol dehydrogenase belong: a. oxidoreductase b. transferase c. hydrolase d. lyase 9. To which class of enzyme does acetyltransferase belong: a. oxidoreductase b. transferase c. hydrolase d. Lyase 10. To which class of enzyme does glutamine synthetase belong: ATP + L-glutamate + NH3 ADP + Pi + L-glutamine a. oxidoreductase b. transferase c. hydrolase d. ligase 11. The reason enzymes increase the rate of chemical reactions is because they a. increase the activation energy required b. lower the activation energy required c. increase the free energy of the compounds formed d. decrease the free energy of the compounds formed 12. a. b. c. d. What is true about Vmax it reflects the concentration of product in a sample it cannot be affected by the temperature of the reaction it cannot be affected by the pH of the reaction it cannot be affected by the substrate concentration 13. Patients who have bone diseases or hepatobiliary diseases would have a higher concentration of a. lactate dehydrogenase b. alkaline phosphatase c. creatine phosphokinase d. α-amylase Classification of Monosaccharides - 3 carbon carbs (trioses) - 4 carbon carbs aldoses ketoses D-/ L- glyceraldehyde Dihydroxyacetone D-/ L- glycerose D-erythrose D-erythrulose D-ribose D-ribulose D-xylose 2’-deoxyribose D-xylulose -6 carbon carbs D-glucose D-fructose (hexoses) D-galactose D-mannose (tetroses) - 5 carbon carbs (pentoses) Sugar monomers bonds hydrolyzed Maltose Dimer of D-glucose (“glucan”) α1-4 maltase Isomaltose Dimer of D-glucose α1-4 isomaltase Sucrose D-glucose & D-fructose α1-2 sucrase (invertase) Lactose D-glucose & D-galactose β1-4 lactase Cellobiose Dimer of D-glucose β1-4 cellulase (bacteria) Trehalose Dimer of D-glucose α1-1 trehalase (microbe) GLUCOSE 6 carbon carbohydrates (hexoses) FRUCTOSE Aldoses D-glucose D-galactose D-mannose Ketose D-fructose Carb monomers Starch D-glucose --amylose --amylopectin branches ~12 res. bonds hydrolyzed α-amylase α1-4 α1-4 & α1-6 into glucose, maltose, isomaltose Glycogen D-glucose branches ~8 res α1-4 & α1-6 α-amylase Cellulose D-glucose: found in plants β1-4 cellulase Inulin D-fructose: found in roots and tubers of lotus, artichokes and dandilions Dietary Fibers Mixture of polysaccharides and non-carbohydrates Dietary Fibers: intrinsic and intact in natural foods. Mixture of un-digestible polysaccharides and noncarbohydrate compounds Cellulose Hemicellulose Pectin Lignin Mucilage Glycoprotein Phytic acid Waxes β14 glucose units Linear D-xylose w/ side chains Soluble polymer of galacuronic acid Methoxy-phenol polymers Sugar acid polymer and galactan mix Extensin is the major form Inositol hexaphosphate, chelating Esters of fatty acids and alcohols ATP ADP 4 ATP made -2 ATP consumed 2 ATP net gain Also 2 NADH hexokinase phosphofructokinase ATP ADP Glyceraldehyde 3-P dehydrogenase Pyruvate kinase Pyruvate dehydrogenase GLYCOLYSIS Glucose Glucose 6-P Glucokinase /hexokinase GLUCONEOGENESIS Glucose 6-P glucose Glucose-6 phosphatase F-6-P F-1,6-BP Phosphofructokinase F-1,6-BP F-6-P PEP Pyruvate Pyruvate kinase Pyruvate oxaloacetate Pyruvate carboxylase Fructose-1,6-bisphosphatase Oxaloacetate PEP PEP carboxykinase Glucose Pyruvate in liver Post-glycolysis Pre-Kreb’s Acetyl-CoA L-alanine Lactate Pyruvate + NAD+ Acetyl CoA + NADH + CO2 Keys to remember: 1. Per glucose, 2 NADH are generated (worth 6 ATP) 2. Pyruvate dehydrogenase “complex” is a regulatory enzyme Three enzymes + five co-factors Pyruvate dehydrogenase Vitamins B1, B2 Dihydrolipoyl transacetylase B3, B5 Dihydrolipoyl dehydrogenase lipoate Aldolase B galactokinase galactose 1-phosphate uridyl transferase Galactosemia: 1. Commonly caused by the deficiency of Gal 1 P uridyl transferase. 2. Sometimes due to a defect of galactokinase Functions of the PPP: 1. Generate NADPH + H+ for lipogenesis 2. Produce ribose-5-phosphate for nucleotide biosynthesis 3. Alternate ‘shunt’ for glucose metabolism 4. Metabolism of some sugars, e.g. xylitol The overall reaction for this process is: Glucose 6-phosphate + 2 NADP+ + H2O → Ribose 5-phosphate + 2 NADPH + 2 H+ + CO2 Glycogenesis Key enzymes: 1. Phosphoglucomutase Isomerizes G—6—P to G—1—P 2. Glycogen synthase Attaches glucose unit (from UDP-Glucose) to an existing primer in α14 3. Branching enzyme a) Removes ~6 glucose chain from growing glycogen polymer b) attaches to a nearby glycogen in α16 Glycogenin: needed for synthesis of glycogen primer (‘glycogenesis’) Key enzymes: 1. Glycogen phosphorylase Breaks α14 bonds of glucose in glycogen to form G—1—P 2. Glucan transferase When a glycogen branch has been reduced to 4 residues, it removes 3 and adds to an existing glycogen polymer branch in α14 linkage 3. Debranching enzyme Removes final α16 of last glucose residue from stump to release glucose Phosphorylates Dephosphorylates Glycogen synthase Glycogen phosphorylase Adrenaline / Epinephrine Insulin + — — + Phosphorylates INACTIVE Phosphorylates ACTIVE Dephosphorylates ACTIVE Dephosphorylates INACTIVE GLUT-1: Passive-facilitative Brain, kidney, placenta, colon, RBCs GLUT-2: Passive-facilitative Liver, pancreatic β cells, kidney Intestineblood (all mono-) GLUT-3: Passive-facilitative Brain, kidney, placenta GLUT-4: ACTIVE Heart, skeletal ms., adipose Insulin-stimulated transporter for active uptake of glucose GLUT-5: Passive-facilitative Intestine For uptake of pentoses For hexoses when [high] Glycosaminoglycans: polymers of carbohydrate derivatives, especially amino sugars and uronic acids (ex: hyaluronic acid, chondroitin sulfate and heparin sulfate) Peptidoglycan: small peptides with attached GAGs generally structural components of cell walls Proteoglycan: proteins with attached GAGs Glycogen: storage form of glucose in animals Carbohydrates 1:30 to answer all three Answer choices for all questions: a. NADH b. NADPH c. FADH2 d. Thiamine pyrophosphate 1. Aerobic glycolysis will result in the NET production of? 2. Which is required for the biosynthesis of polyols such as sorbitol 3. The function of the pentose phosphate pathway results in the net production of which one 1:30 to answer all three Answer choices for all questions: a. NADH b. FADH2 c. GTP d. CO2 4. Which is required for the conversion of pyruvate to oxaloacetate (in gluconeogenesis) 5. Which is required for the action of phosphoenolpyruvate carboxykinase (in gluconeogenesis) 6. Which is an END product formed by the pyruvate dehydrogenase complex (pick 2) 1:00 to answer both 7. a. b. c. d. Which one catalyzes the conversion of ADP to ATP D-glyceraldehyde-3-phosphate dehydrogenase Phosphofructokinase Lactate dehydrogenase Pyruvate kinase 8. a. b. c. d. Which one catalyzes the conversion of ATP to ADP D-glyceraldehyde-3-phosphate dehydrogenase Phosphofructokinase Lactate dehydrogenase Pyruvate kinase 1:00 to answer both 9. Which one is used in glycogenesis a. Glycogen synthase b. Glycogen phosphorylase c. Glycogen decarboxylase d. Debranching enzyme 10. Which one is responsible for α1-6 bonding in glycogenesis a. Glycogen synthase b. Glycogen phosphorylase c. Branching enzyme d. Debranching enzyme 1:30 to answer all three 11. The deficiency of which one is related to galactosemia a. Glucose-6-phosphate dehydrogenase b. Pyruvate carboxylase c. Aldolase B d. Galactosyl-1-phosphate uridyltransferase 12. FAD is reduced to FADH2 in which one a. Aerobic glycolysis b. Anaerobic glycolysis c. Kreb’s cycle d. Electron transport chain 13. a. b. c. d. Pyruvate is the end product formed in which one Aerobic glycolysis Anaerobic glycolysis Kreb’s cycle Electron transport chain 1:30 to answer all three Answer choices for all questions: a. Phosphofructokinase b. Glyceraldehyde-3-phosphate dehydrogenase c. Lactate dehydrogenase d. Pyruvate kinase 14. Which one catalyzes the formation of NADH in both aerobic and anaerobic glycolysis 15. In the cell, which one catalyzes the formation of NADH only under aerobic (not anaerobic) conditions 16. Pi, a low energy metabolite in the body, can stimulate the activity of which one in an allosteric manner 1:30 to answer all three Answer choices for all questions: a. NADH b. NADPH c. CoASH d. Thiamine pyrophosphate 17. Which one is required for the conversion of pyruvate to acetyl-CoA (pick 2) 18. There is a NET production of which one when pyruvate is converted to acetyl-CoA 19. Which one is required for the conversion of pyruvate to lactate under anaerobic conditions 1:30 to answer all three Answer choices for all questions: a. Aerobic glycolysis b. Anaerobic glycolysis c. Glycogenesis d. Glycogenolysis 20. In which pathway is the end product glucose-1phosphate 21. Which pathway is most active under “carbohydrate loading” 22. Which pathway is most active in the liver when trying to maintain blood glucose levels Answer choices for all questions: a. NADH b. NADPH c. FADH2 d. Thiamine pyrophosphate 1. Aerobic glycolysis will result in the NET production of? A 2. Which is required for the biosynthesis of polyols such as B sorbitol 3. The function of the pentose phosphate pathway results in the B net production of which one Answer choices for all questions: a. NADH b. FADH2 c. GTP d. CO2 4. Which is required for the conversion of pyruvate to D oxaloacetate (in gluconeogenesis) 3 carbon 4 carbon) 5. Which is required for the action of phosphoenolpyruvate C carboxykinase (in gluconeogenesis) 6. Which is an END product formed by the pyruvate dehydrogenase complex (pick 2) A, D 7. a. b. c. d. Which one catalyzes the conversion of ADP to ATP D-glyceraldehyde-3-phosphate dehydrogenase Phosphofructokinase Lactate dehydrogenase Pyruvate kinase 8. a. b. c. d. Which one catalyzes the conversion of ATP to ADP D-glyceraldehyde-3-phosphate dehydrogenase Phosphofructokinase Lactate dehydrogenase Pyruvate kinase 9. Which one is used in glycogenesis a. Glycogen synthase b. Glycogen phosphorylase c. Glycogen decarboxylase d. Debranching enzyme 10. Which one is responsible for α1-6 bonding in glycogenesis a. Glycogen synthase b. Glycogen phosphorylase c. Branching enzyme d. Debranching enzyme 11. The deficiency of which one is related to galactosemia a. Glucose-6-phosphate dehydrogenase b. Pyruvate carboxylase c. Aldolase B d. Galactosyl-1-phosphate uridyltransferase 12. FAD is reduced to FADH2 in which one a. Aerobic glycolysis b. Anaerobic glycolysis c. Kreb’s cycle d. Electron transport chain 13. a. b. c. d. Pyruvate is the end product formed in which one Aerobic glycolysis Anaerobic glycolysis Kreb’s cycle Electron transport chain Answer choices for all questions: a. Phosphofructokinase b. Glyceraldehyde-3-phosphate dehydrogenase c. Lactate dehydrogenase d. Pyruvate kinase 14. Which one catalyzes the formation of NADH in both B aerobic and anaerobic glycolysis 15. In the cell, which one catalyzes the formation of NADH C only under aerobic (not anaerobic) conditions 16. Pi, a low energy metabolite in the body, can stimulate the A activity of which one in an allosteric manner Pi = low energy state Regulates one of the key enzymes of glycolysis Answer choices for all questions: a. NADH + H+ b. NADPH + H+ c. CoASH d. Thiamine pyrophosphate 17. Which one is required for the conversion of pyruvate to acetyl-CoA (pick 2) C, D 18. There is a NET production of which one when pyruvate is converted to acetyl-CoA A 19. Which one is required for the conversion of pyruvate to lactate under anaerobic conditions A Answer choices for all questions: a. Aerobic glycolysis b. Anaerobic glycolysis c. Glycogenesis d. Glycogenolysis 20. In which pathway is the end product glucose-1phosphate D 21. Which pathway is most active under “carbohydrate loading” C 22. Which pathway is most active in the liver when trying to maintain blood glucose levels D Isocitrate Keys 3 NADHs get made 1 FADH2 gets made 1 GTP gets made Acetyl-CoA gets consumed Both CO2 come from acetyl-CoA ENZYME ACTIVATOR INHIBITOR Citrate Synthase High NAD High ATP Isocitrate Dehydrogenase High ADP High ATP and NADH α-ketoglutarate dehydrogenase CoASH, pyruvate, high ADP Fatty acids, ketone bodies, High NADH Succinate thiokinase Mg2+ /dehydrogenase Oxaloacetate 1. Occurs in the mitochondria 2. Functions under aerobic conditions only 3. Two carbons are oxidized to CO2, and the energy from these reactions is stored in GTP, NADH and FADH2 4. NADH and FADH2 are coenzymes that store energy and are utilized in oxidative phosphorylation (ETC) 5. Because TWO acetyl-CoA molecules are produced from each glucose molecule, two cycles are required per glucose. 6. At the end of all cycles from one glucose, the products are two GTP, six NADH, two FADH2, four CO2. 7. The cycle is regulated by allosteric inhibition at rest 8. NADH is produced by dehydrogenase reactions 9. FADH2 is produced by succinate dehydrogenase 10. GTP is formed by succinyl-CoA synthetase Complex I Complex III Complex IV Complex II Keys of Electron Transport Chain (ETC): 1. ETC members are embedded in the inner mitochondrial membrane 2. NADH is the primary electron donor 3. Oxidation of each NADH yields 3 ATP, each FADH2 yields 2 ATP 4. Complexes I, III and IV are proton pumps, while Q and cytochrome c are mobile electron carriers. 5. ATP is generated from ADP + Pi by ATP Synthase 6. No direct regulation of the ETC Enzyme Reaction catalyzed Pathway Molecule generated Phosphoglycerate kinase 1,3-BPG to 3PG Glycolysis ATP Pyruvate kinase PEP to pyruvate Glycolysis ATP Succinyl-CoA synthetase Succinyl-CoA to succinate Kreb’s cycle GTP ATP synthase ADP to ATP ETC ATP Creatine (phospho)kinase Phosphocreatine to Skeletal creatine muscle and brain ATP Energetics 1:30 to answer all three 1. The coenzyme form of which ones are involved in oxidative phosphorylation (pick 2) a. Vitamin B1 b. Vitamin B2 c. Vitamin B3 d. Vitamin B6 2. The Kreb’s cycle results in a NET production of which ones (pick 2) a. NADH b. NADPH c. FADH2 d. Thiamine pyrophosphate 3. Which is the first enzyme in the Kreb’s cycle. It catalyzes the reaction between Acetyl-CoA and oxaloacetate a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 1:30 to answer all four Answer choices for all questions a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 4. Which one catalyzes the formation of GTP 5. Which one catalyzes the formation of FADH2 6. Which one catalyzes the formation of NADH 7. Which catalyzes the formation of CO2 1:30 to answer all three 8. Mg2+ is required for the activity of which one a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 9. Which can be formed by the action of malate dehydrogenase a. Acetyl-CoA b. GTP c. NADH d. FADH2 10. The carbons in the CO2 released in the Kreb’s cycle were originally in which molecule a. Acetyl-CoA b. GTP c. NADH + H+ d. FADH2 1. The coenzyme form of which ones are involved in oxidative phosphorylation (pick 2) a. Vitamin B1 b. Vitamin B2 c. Vitamin B3 d. Vitamin B6 2. The Kreb’s cycle results in a NET production of which ones (pick 2) a. NADH b. NADPH c. FADH2 d. Thiamine pyrophosphate 3. Which is the first enzyme in the Kreb’s cycle. It catalyzes the reaction between Acetyl-CoA and oxaloacetate a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 4. Which one catalyzes the formation of GTP a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 5. Which one catalyzes the formation of FADH2 a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 6. Which one catalyzes the formation of NADH a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 7. Which catalyzes the formation of CO2 a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 8. Mg2+ is required for the activity of which one a. citrate synthase b. succinate dehydrogenase c. α-ketoglutarate dehydrogenase d. succinate thiokinase 9. Which can be formed by the action of malate dehydrogenase a. Acetyl-CoA b. GTP c. NADH d. FADH2 10. The carbons in the CO2 released in the Kreb’s cycle were originally in which molecule a. Acetyl-CoA b. GTP c. NADH + H+ d. FADH2 1. Triglycerides Fat and oil 2. Phospholipids Lecithin, etc 3. Isoprene lipids Carotenoids, Vit A, etc 4. Steroid lipids Cholesterol, etc 5. Sphingolipids Sphingomyelin, glycolipids 6. Lipid derivatives Eicosanoids, lipoprotein, etc Saturated (SAFA): Possess ONLY single bonds between carbons Mono unsaturated (MUFA): Primarily in animal fats 50:50 Possess ONE double bond per molecule Polyunsaturated (PUFA):Primarily in vegetable oils Possess at least two double bonds between carbons Exceptions: plant oils with little PUFA Coconut oil High in medium-chain fatty acids C10-C14 Olive oil High in oleic acid, a C18 MUFA C18:1,9 PUFAs that cannot be synthesized by the human body linoleic acid and α-linolenic acid “LA” and “ALA” PUFAs not synthesized in significant amounts γ-linolenic acid, arachidonic acid and eicosapentaenoic acid “GLA” “AA” “EPA” C20:3;8,11,14 (DGLA) ω-6 PG1 LT3 1 3 C20:4;5,8,11,14 (AA) PG2 LT4 PGI2 TX2 2 4 2 2 PG3 LT5 PGI3 TX3 3 5 3 3 ω-6 C20:5,5,8,11,14,17 (EPA) ω-3 Lipoproteins are responsible for transport of lipids Lipoprotein Chylomicron VLDL IDL Carry TGs from intestines to liver and adipose Carry newly synthesized TGs from liver to adipose ↑ FC and CE LDL ↑ FC and CE; carry cholesterol from liver to other tissues; “Bad cholesterol” HDL Scavenges cholesterol from body’s tissues/blood to liver; “Good cholesterol” FFA, monoacylglycerol, glycerol, cholesterol and lysophospholipids enter intestinal mucosal cells re-esterify to form TG, PL and CE aggregate with apolipoproteins and free cholesterol to form chylomicrons released by exocytosis into the lymph Blood transported to liver, adipose, cardiac & skeletal ms catabolized by lipoprotein lipase into VLDLs Lipoprotein lipase at peripheral tissue… activated by PL and apo-C remnant To get LDL into peripheral tissues, the tissues must have a receptor: LDL receptor apo-C, apo-E Nascent VLDL apo-C VLDL apo-C, apo-E IDL LDL Tissues E: Endosome L: Lysosome ACAT: Acyl-CoA-cholesterol acyl transferase Primarily produced by liver (some in sm. intestine) Circulating HDL picks up free cholesterol from peripheral tissues PUFA from lecithin Free cholesterol Cholesteryl ester LCAT: Lecithin cholesterol acyl transferase Transfer cholesteryl esters to LDL or chylomicron remnants for deposition in tissues increase in size as they circulate through the bloodstream by incorporating more cholesterol sequestered into the core of the HDL lipoprotein Adipose Triglycerides are mobilized by Hormone-Sensitive Triglyceride Lipase (“Hormone-sensitive lipase”) TG HSL lipolysis Free Fatty acid + Diacylglycerol Diacylglycerol Other enzymes lipolysis Free fatty acids are released from the cell bind serum albumin transported in blood liver (and other tissues) utilized for energy Free fatty acids + glycerol lipoprotein lipase: cleaves lipoproteins (VLDL, chylomicrons) releases triglycerides for tissues phospholipase A2: cleaves phospholipids (and sphinogmyelins) releases fatty acids for eicosanoid synthesis hormone-sensitive lipase: cleaves stored fats (adipocytes) releases fatty acids for gluconeogenesis acetyl-CoA carboxylase: converts acetyl-CoA to malonyl-CoA for fatty acid synthesis Acyl-CoA + CoASH + FAD + NAD + H2O Acetyl-CoA + Acyl-CoA + FADH2 + NADH The FADH2 + NADH are further oxidized in the electron transport chain for ATP formation Note: If EVEN # of carbons in fatty acid If ODD # of carbons in fatty acid Acetyl-CoA Propionyl-CoA Transport of Acyl-CoA into mitochondria using carnitine as a carrier CPT I CPT II Glucose Malonyl-CoA 3C CO2 ADP ATP CO2 acyl-CoA Cn+2 Acetyl-CoA 2C ATP- Citrate lyase Citrate Protein CoASH 3-ketoacyl-CoA Cn+2 2 NADPH + H+ acyl-CoA Cn+2 2 NADP + H2O Desaturase Systems: Enzymes responsible for creating double bonds The desaturase functions with the elongase system to synthesize longer unsaturated fatty acids Regarding PUFAs: Humans can only place double bonds between the carboxyl group and the first double bond Not between the first double bond and the last carbon Ketone Bodies Acetone β-hydroxybutyrate Acetoacetate Although ketogenic amino acids can be converted to ketone bodies, most come from β-oxidation Excessive β-oxidation acetoacetyl-CoA + acetyl-CoA HMG-CoA HMG-CoA Synthase HMG-CoA Lyase Acetone β-hydroxybutyrate Acetoacetate + Acetyl-CoA CYTOPLASM MITOCHONDRIA 2 Acetyl-CoA CoASH + Acetoacetyl-CoA Acetyl-CoA CoASH CoASH + Mevalonate ATP + Mg2+ & decarboxylation HMG-CoA reductase 2 NADP HMG-CoA 2 NADPH + H+ 6 Isopentenyl pyrophosphate (5C) Cholesterol (27C) Key Regulatory Enzyme: HMG-CoA reductase Decreased activity 1. Fasting 2. Cholesterol 3. Dietary cholesterol 4. Statins (analog drugs of mevalonate) … like Lipator 5. Glucagon and glucocorticoids Increased activity 1. Insulin Multiple sclerosis: Lack of sphingolipids in white matter Cholesteryl esters found in white matter CSF has elevated levels of phospholipids Deficiency of GABA Niemann-Pick disease: Deficiency of sphingomyelinase Signs: enlarged liver and spleen, MR, fatal early in life Tay-Sach’s disease: Defect of hexoseaminidase build up of gangliosides Signs: MR, blindness, muscular weakness Lipids 1:30 to answer all four Answer choices for all questions: a. Acetyl-CoA b. CO2 c. NADPH d. ATP 1. Which one is produced in the tricarboxylic acid cycle? 2. Which one is produced in the pentose phosphate pathway? 3. A large amount of which one is produced in the electron transport chain? 4. Which one is the direct chief energy source for biochemical reactions? 1:30 to answer all three Answer choices for all questions: a. Linoleic acid b. Arachidonic acid c. Butyric acid d. Eicosapentaenoic acid 5. Which one DOES NOT lead to the production of malondialdehyde? 6. The eicosanoids derived from which one is good for preventing heart attack and stroke? 7. The eicosanoids derived from which one are mediators of allergic reactions and thrombosis? 1:30 to answer all four Answer choices for all questions: a. Chylomicrons b. VLDL c. LDL d. HDL 8. Which one is primarily responsible for removing peripheral cholesterol back to the liver for metabolism 9. Which one is responsible for the transport of dietary lipids from the intestine into the body tissues 10. Which one is primarily responsible for the transport of endogenously synthesized lipids from the liver to the peripheral tissues 11. The receptor for which one is defective in the liver of familial hypercholesterolemia victims 2:00 to answer all four Answer choices for all questions: a. Pancreatic lipase b. Lipoprotein lipase c. Hormone-sensitive lipase d. Phospholipase A2 12. Anti-inflammatory steroids work by inhibiting which one? 13. Which one is responsible for the digestion of dietary lipids in the gut? 14. Which one is essential for the transfer of lipids from blood into cells? 15. Which one is responsible for the lipolysis of triglycerides in adipocytes? 2:30 to answer all four 16. When palmitoyl-CoA is oxidized through β-oxidation, eight molecules of which one are formed? (pick 2) a. Thiokinase b. Carnitine c. NADH + H+ d. Acetyl-CoA 18. In the fed state, high dietary fat does not cause ketosis because activity of which one is inhibited by malonyl-CoA? a. Acetyl-CoA carboxylase b. Carnitine-palmitoyltransferase I c. HMG-CoA reductase d. Desaturase 17. ATP and Mg2+ are required for the activity of which one? a. Acetyl-CoA carboxylase b. Carnitine-palmitoyltransferase I c. HMG-CoA reductase d. Desaturase 19. Acetoacetate is synthesized in which pathway? a. Glycolysis b. β-oxidation c. Lipogenesis d. Ketogenesis Answer choices for all questions: a. Acetyl-CoA b. CO2 c. NADPH d. ATP B C 1. Which one is produced in the tricarboxylic acid cycle? 2. Which one is produced in the pentose phosphate pathway? 3. A large amount of which one is produced in the electron D transport chain? 4. Which one is the direct chief energy source for biochemical D reactions? Answer choices for all questions: a. Linoleic acid b. Arachidonic acid c. Butyric acid d. Eicosapentaenoic acid 5. Which one DOES NOT lead to the production of malondialdehyde? C 6. The eicosanoids derived from which one is good for preventing heart attack and stroke? D 7. The eicosanoids derived from which one are mediators of allergic reactions and thrombosis? B Answer choices for all questions: a. Chylomicrons b. VLDL c. LDL d. HDL 8. Which one is primarily responsible for removing peripheral cholesterol back to the liver for metabolism D 9. Which one is responsible for the transport of dietary lipids A from the intestine into the body tissues 10. Which one is primarily responsible for the transport of B endogenously synthesized lipids from the liver to the peripheral tissues 11. The receptor for which one is defective in the liver of C familial hypercholesterolemia victims Answer choices for all questions: a. Pancreatic lipase b. Lipoprotein lipase c. Hormone-sensitive lipase d. Phospholipase A2 12. Anti-inflammatory steroids work by inhibiting which one? D 13. Which one is responsible for the digestion of dietary lipids A in the gut? 14. Which one is essential for the transfer of lipids from blood B into cells? 15. Which one is responsible for the lipolysis of triglycerides C in adipocytes? 16. When palmitoyl-CoA is oxidized through β-oxidation, eight molecules of which one are formed? a. Thiokinase b. Carnitine c. NADH + H+ d. Acetyl-CoA 17. ATP and Mg2+ are required for the activity of which one? a. Acetyl-CoA carboxylase b. Carnitine-palmitoyltransferase I c. HMG-CoA reductase d. Desaturase 18. In the fed state, high dietary fat does not cause ketosis because activity of which one is inhibited by malonyl-CoA? a. Acetyl-CoA carboxylase b. Carnitinepalmitoyltransferase I c. HMG-CoA reductase d. Desaturase 19. Acetoacetate is synthesized in which pathway? a. Glycolysis b. β-oxidation c. Lipogenesis d. Ketogenesis “Essential” Amino Acids cannot be synthesized by the body. Phenylalanine Valine Threonine Tryptophan Isoleucine Methionine Histidine Arginine Leucine Lysine (Phe, F) (Val, V) (Thr, T) (Trp, W) (Ile, I) (Met, M) (His, H) (Arg, R) (Leu, L) (Lys, K) PVT TIM HALL Adults can synthesize Adults can synthesize Aliphatic: Gly, Ala, Val, Leu, Ile Hydroxyl: Ser, Thr, Tyr, Hyl, Hyp Sulfer: Cys, Met Carboxyl/amide: Asp, Glu / Asn, Gln Basic: Lys, Arg, His, Hyl Aromatic: His, Phe, Tyr, Trp Pyrrolidine: Pro, Hyp Pyrrolidine Amide bond: (aka peptide), between COOH and NH3. Catalyzed by enzymes Glycosidic bond: proteins covalently attached to carbohydrates Zwitterion: molecule with both positive and negative charges Isoelectric point: when the sum of all positive charges equals the sum of all negative charges. Net zero charge Catechol Catecholamine No longer an amino acid Fate of pyruvate Glucose Pyruvate in liver Post-glycolysis Pre-Kreb’s Acetyl-CoA L-alanine Lactate 1. Glutathione (GSH): intracellular antioxidant 2. Thyrotropin-releasing hormone (TRH): tripeptide from hypothalamus, stimulates pituitary 3. Substance P: Pain neurotransmitter 4. Kinins (Bradykinin and Kallidin): vasodilating 5. Opiopeptides: analgesic action Enkaphalin Beta-endorphin Dynorphin Orexigenic: Peptides that INCREASE appetite Released by Agouti-related peptide Neuropeptide Y Melanin Concentrating Hormone (MCH) Orexins (hypocretins) Insulin Ghrelin Brain Brain Brain Brain Pancreas Stomach Anorexigenic: Peptides that DECREASE appetite Released by Peptide YY: blocks ghrelin Glucagon-like peptide: delays stomach emptying, acts on satiety center in brain Cholecystokinin Melanocortin: binding R inhibits intake Leptin: regulates intake of kcal, C, F, but not percentages of each Does not prevent obesity Intestine Intestine Intestine Brain Adipocyte Primary Structure: Specific amino acid sequence Connected by peptide bond (covalent amide bond) which can be hydrolyzed by proteases or boiling Primary structure is dictated by codons in genes Primary structure dictates subsequent organization Secondary Structure: α-helix β-pleated sheet β-bending Random coil H-bonding Tertiary Structure: 3-D structure of protein 3-D structure related to function Examples: the enzyme catalytic site which forms a pocket for a specific substrate H-bonds, ionic bonds, hydrophobic interactions, and disulfide bonds Quaternary Structure: More than 1 polypeptide subunit (aka monomer) H-bonds, ionic bonds, hydrophobic interactions Degree of subunit association affects function Collagen Most abundant protein in the body Mature tropocollagen composed of 3 α-chain subunits held together by H-bonds Glycine is the most abundant amino acid in collagen, with lots of proline and lysine Hydroxylation of Proline by prolyl hydroxylase and Lysine by lysyl hydroxylase Req’s Fe, Vit C, and O2 Histidine histamine Phenylalanine tyrosine catecholamines 1. dopamine 2. norepinephrine 3. epinephrine Tryptophan serotonin Tyrosine melanins Amination (NH4+) or Amidation (NH2) synthesis of aspartatic acid and glutamic acid NADPH + H+ Oxaloacetate+ NADP Aspartate NH4+ NADH + H+ KREB’s CYCLE H2O NAD Glutamate dehydrogenase NADPH + H+ α-ketoglutarate + NADP Glutamate NH4+ NADH + H+ H2O NAD Classified into the following reaction types: Amination (NH4) or Amidation (NH2) synthesis of asparagine and glutamine Glutamate+ NH4+ + ATP Glutamine synthetase Glutamine + ADP + Pi Mg2+ Aspartate+ NH4+ + ATP Asparagine synthetase Asparagine + ADP + Pi Classified into the following reaction types: Transamination with transaminases and B6PO4 Pyruvate + Alanine NH2 Glutamate Oxaloacetate + NH2 Glutamate 3-P-glycerate + NH2 Glutamate aminotransferase Alanine + α-ketoglutarate B6PO4 Aspartate aminotransferase 3 Steps Aspartate + α-ketoglutarate Serine The left over amino acids a. Serine Glycine b. Glutamate Proline c. Methionine + Serine Cysteine d. Aspartate + Glutamine Asparagine e. Urea cycle Arginine 1. The urea cycle consists of five reactions - two mitochondrial and three cytosolic. 2. Requirements for Urea synthesis: The cycle converts two amino groups (one from NH4+ and one from Asp) 3. Cost: four "high-energy" phosphate bonds (3 ATP hydrolyzed to 2 ADP and one AMP). Summary reaction: NH3 + aspartate + HCO3- + 3 ATP → urea + fumarate + 2 ADP + 1AMP + 4 Pi (2nd NH3)(4 bonds) 4. The Urea Cycle is the site of Arginine synthesis Branch-chain amino acids Amino group Pyruvate Alanine Alanine LIVER deamination NH3 UREA glycolysis Glucose Glucose gluconeogenesis Pyruvate Maple syrup urine disease: Defect in metabolism of branch-chain amino acids Phenylketonuria: Genetic deficiency of phenylalanine hydroxylase Alkaptonuria (Dark urine disease): Tyrosine metabolism is interrupted Primary hyperoxaluria: Vitamin B6 deficiency inhibits glycine transaminase Sulfite oxidase dysfunction: Cysteine amino acid metabolism is disrupted Albinism: Defect in tyrosinase Glycine + succinyl CoA Protoporphyrin III Protoporphyrin III + Fe2+ = Heme Hyperbilirubinemia: When blood [bilirubin] > 1 mg/dL When blood [bilirubin] > 20-25 mg/dL, it penetrates tissues and results in jaundice (icterus) Unconjugated hyperbilirubinemia (Retention type): Not conjugated to glucuronate. No bilirubin detected in urine Conjugated hyperbilirubinemia (Regurgitation type): Conjugated to glucuronate to form bilirubin diglucuronate Small peptides are further digested to amino acids in the intestine wall by peptidases Disaccharides are digested in the small intestine by dissacharidases (e.g. maltase) Dietary Guidelines 0.8g/kg body weight 1.2g/kg during pregnancy and lactation 12-15% total daily kcal Soybean Nuts Peanut Other Legume - + - + - + - Blank: adequate + + - + High -Low + Gelatin Green leafy veggies Sesame Sunflower seed Grain Cereal - Meat Eggs Dairy - Met Ile Leu Lys Phe Thr Trp Val + + + + + + + - - + EAA Consequence: Kwashiorkor: “Disease of the first child” Protein-Energy Malnutrition (PEM) Due to chronic protein deficiency Signs/Sx: Weakness, edema, loss of hair, skin lesions, diarrhea, fatty liver, recurrent infections (MCC death is infection). Marasmus: Total deficiency of all ergogenic macronutrients (C, P, F) No edema. Leads to total loss of body mass Diabetes (insulin resistance) Hypercalciuria Osteoporosis Elevated (kidney stones) (bone resorption) BUN (Blood Urea Nitrogen) Amino Acids and Protein 1:30 to answer all four Answer choices for all questions: a. Lysine b. Tyrosine c. Tryptophan d. Glycine 1. Which one is a nutritionally essential amino acid? 2. Which one is ketogenic only (it cannot be glycogenic)? 3. L-DOPA, a drug for Parkinson’s disease, is actually synthesized in the body from which one? 4. Serotonin, a neurotransmitter related to sleep, is synthesized in the body from which precursor? 1:30 to answer all four Answer choices for all questions: a. Lysine b. Tyrosine c. Tryptophan d. Glycine 5. Catecholamines are synthesized from which precursor 6. The nitrogen atom of heme is derived from which amino acid 7. The skin pigment melanin is derived from which precursor amino acid 8. Adrenaline is derived from which one 2:00 to answer all four Answer choices for all questions: a. Glutamate dehydrogenase b. Alanine aminotransferase c. Prolyl hydroxylase d. Glutamine synthase 9. Which one cannot function without a coenzyme derived from vitamin B6 10. Which one cannot function without vitamin C 11. Which one cannot function without a coenzyme derived from niacin 12. The action of which one is critically related to the formation of mature collagen 1:30 to answer all three Answer choices for all questions: a. Hyperammonemia b. Alkaptonuria c. Phenylketonuria d. Maple syrup urine disease 13. Which one could be caused by a deficiency in urea cycle enzymes? 14. Which one is due to the defect of the enzyme responsible for the metabolism of the α-keto acids of the branch chain amino acids? 15. Which one is due to the defect of homogentisate oxidase, an enzyme involved in the catabolism of tyrosine? 1:30 to answer all three Answer choices for all questions: a. Hyperammonemia b. Alkaptonuria c. Phenylketonuria d. Maple syrup urine disease 16. Which one is due to the deficiency of phenylalanine hydroxylase 17. Which one is due to the deficiency of glycine transaminase 18. Which one can lead to black bone and dark urine 1:30 to answer all three Answer choices for all questions: a. Prolyl hydroxylase b. Carbamoyl phosphate synthase c. Arginase d. L-α-amino acid oxidase 19. Vitamin C and Fe2+ are cofactors for which one 20. Which one catalyzes the deamination of amino acids to form ammonia 21. Deficiency of which one is most likely to result in hyperammonemia Answer choices for all questions: a. Lysine b. Tyrosine c. Tryptophan d. Glycine 1. Which one is a nutritionally essential amino acid? A 2. Which one is ketogenic only (it cannot be glycogenic)? A 3. L-DOPA, a drug for Parkinson’s disease, is actually B synthesized in the body from which one? 4. Serotonin, a neurotransmitter related to sleep, is synthesized C in the body from which precursor? Answer choices for all questions: a. Lysine b. Tyrosine c. Tryptophan d. Glycine 5. Catecholamines are synthesized from which precursor B 6. The nitrogen atom of heme is derived from which amino D acid 7. The skin pigment melanin is derived from which precursor B amino acid 8. Adrenaline is derived from which one B Answer choices for all questions: a. Glutamate dehydrogenase b. Alanine aminotransferase c. Prolyl hydroxylase d. Glutamine synthase 9. Which one cannot function without a coenzyme derived from vitamin B6 B 10. Which one cannot function without vitamin C C 11. Which one cannot function without a coenzyme derived from niacin A 12. The action of which one is critically related to the formation of mature collagen C Answer choices for all questions: a. Hyperammonemia b. Alkaptonuria c. Phenylketonuria d. Maple syrup urine disease 13. Which one could be caused by a deficiency in urea cycle enzymes? A 14. Which one is due to the defect of the enzyme responsible for the metabolism of the α-keto acids of the branch chain D amino acids? 15. Which one is due to the defect of homogentisate oxidase, an B enzyme involved in the catabolism of tyrosine? Answer choices for all questions: a. Hyperammonemia b. Alkaptonuria c. Phenylketonuria d. Maple syrup urine disease 16. Which one is due to the deficiency of phenylalanine hydroxylase C 17. Which one is due to the deficiency of glycine transaminase A 18. Which one can lead to black bone and dark urine B Answer choices for all questions: a. Prolyl hydroxylase b. Carbamoyl phosphate synthase c. Arginase d. L-α-amino acid oxidase 19. Vitamin C and Fe2+ are cofactors for which one A 20. Which one catalyzes the deamination of amino acids to form ammonia D 21. Deficiency of which one is most likely to result in hyperammonemia B 5’-phosphate 2’-deoxyribose phosphodiester bond: connects monomers together H 3’-hydroxyl Purines Possess a 2-ring heteronitrogen structure Adenine (A) Occur in nucleic Guanine (G) acids Xanthine (X) or their metabolites Hypoxanthine (Hx) Caffeine Theophylline Theobromine Occur in food Pyrimidines Possess a 1-ring heteronitrogen structure Cytosine (C) Found in both RNA and DNA Found in RNA only Uracil (U) Thymine (T) Found in DNA only RNA has ribose DNA has deoxyribose Nucleoside: nitrogen base + ribose Nucleotide: nucleoside + phosphate (1, 2, or 3) Synthesis of all nucleotides BASE + Phosphoribose as “PRPP” PRPP: Phosphoribosyl Pyrophosphate DNA Antiparallel double helix Hydrogen bonds A binds with T (2 H-bonds) C binds with G (3 H-bonds) Replication is “semi-conservative” Begins with RNA primer DNA is always synthesized 5’ 3’ Contains the codons for directing the sequence of the amino acids of a polypeptide (protein) Each mRNA has a cap (head) which is 7methylguanosine triphosphate (GmTP) Following is an INITIATION (leading) codon, AUG, coding for methionine. A tail at the end is made of many adenosine monophosphates, called ‘poly-A tail’ Codon: Three monophosphate nucleotides that code for a particular amino acid. Cloverleaf structure with 4 arms: “hairpin loops” tRNAs transfer the amino acids to the ribosomal site where protein synthesis is taking place At least 20 tRNAs for the 20 amino acids used in proteins One arm has anticodon: matches a codon on mRNA (H-bonds to codon like DNA… C=G , A=T) Note: 3’ end has CCA which carries a specific amino acid (dictated by the codon) E1: G6Pase (von Gierke’s) E2: PRPP Synthetase E8: DNase E6: RNase E4: Ribonucleotide reductase E5: HGPTase (Lesch-Nyhan) E7: Xanthine Oxidase (hypouricemia) E9: Adenosine Deaminase (SCID) E9 E4 E1:Carbamoyl Phosphate Synthetase E2: Aspartate Transcarbamoylase E3: PRPP Synthetase Inhibited by CTP Stimulated by PRPP Inhibited by UTP Inhibited by all mono and diphosphate nts Purine Nitrogen base: a. Amino acids: Gln, Asp, Gly b. CO2 c. Coenzyme: Folate Pyrimidine Gln, Asp NAD, NADPH Folate For Pentose Phosphate: a. Pentose : R-5-P + ATP PRPP (via PRPP synthetase) To form a. Cofactor: b. Energy: IMP Mg++ ATP OMP Mg++ ATP Nucleotides and Nucleic Acids 3:00 to answer all eight Answer choices for all questions: a. DNA b. mRNA c. rRNA d. tRNA 1. Thymine occurs in which one? 2. In humans, genes are segments of which one? 3. Which one is composed of codons and is directly responsible for the amino acid sequence of a protein? 4. Which one possesses an anticodon and is responsible for the transfer of amino acids to the site of protein synthesis? 5. In humans, the molecule of which one entirely exists as an antiparallel double helix? 6. Which one has 7 methyl guanosine triphosphate at the 5’ end? 7. Which one possesses a polyA tail at the 3’ end? 8. Which one complexes with proteins to form ribosomes? 1:30 to answer all three Answer choices for all questions: a. Ribose-5-phosphate b. 2’-deoxythymidine-5’-phosphate c. Allopurinol d. Uric Acid 9. Which one is a synthetic purine compound and could be used to treat gout? 10. Which one is required for the biosynthesis of purine nucleotides? 11. Which one is required for the biosynthesis of pyrimidine nucleotides? 2:00 to answer all four Answer choices for all questions: a. Reverse transcriptase b. Restriction endonuclease c. Protein tyrosine kinase d. Peptidyl transferase 12. Which one is responsible for the formation of the peptide bond between amino acid residues in protein translation? 13. Which one is responsible for generating blunt or sticky ends of DNA? 14. AZT, a drug used to treat AIDS patients, is an inhibitor of which one? 15. The activity of which one is believed to initiate cell division resulting in cancer? Answer choices for all questions: a. DNA b. mRNA c. rRNA d. tRNA 1. Thymine occurs in which one? A 2. In humans, genes are segments of which one? A 3. Which one is composed of codons and is directly responsible B for the amino acid sequence of a protein? 4. Which one possesses an anticodon and is responsible for the D transfer of amino acids to the site of protein synthesis? 5. In humans, the molecule of which one entirely exists as an A antiparallel double helix? 6. Which one has 7 methyl guanosine triphosphate at the 5’ end? B 7. Which one possesses a polyA tail at the 3’ end? B 8. Which one complexes with proteins to form ribosomes? C Answer choices for all questions: a. Ribose-5-phosphate b. 2’-deoxythymidine-5’-phosphate c. Allopurinol d. Uric Acid 9. Which one is a synthetic purine compound and could be used to treat gout? C 10. Which one is required for the biosynthesis of purine nucleotides? A 11. Which one is required for the biosynthesis of pyrimidine nucleotides? A Answer choices for all questions: a. Reverse transcriptase b. Restriction endonuclease c. Protein tyrosine kinase d. Peptidyl transferase 12. Which one is responsible for the formation of the peptide bond D between amino acid residues in protein translation? 13. Which one is responsible for generating blunt or sticky ends of DNA? B 14. AZT, a drug used to treat AIDS patients, is an inhibitor of which one? A 15. The activity of which one is believed to initiate cell division resulting in cancer? C Characteristics of vitamins: Cannot be synthesized by mammalian cells and, therefore, must be supplied in the diet. Exceptions: made by humans Vitamin D3 –Fat soluble vitamin made in skin Vitamin B3 (niacin) –Water soluble made in cells Exceptions: made by bacteria in our gut Vitamin K –Fat soluble Vitamin B7 (biotin) –Water soluble Fat soluble Water soluble Solubility Good in fat/oil and organics Good in water Absorption Increased by fatty food By intestinal capillaries (except B12) Transport By specific proteins or lipoproteins By plasma, except B12 and folate Storage Significant. Mostly liver and adipose Lower. Mostly internal organs and muscle Function Varies Mostly as coenzymes and antioxidants Active site Cellular lipid components / nucleus Aqueous cellular components Excretion Slow, via bile Fast; via urine Deficiency Presents slowly Presents rapidly Toxicity high, except Vit E Relatively low, except B3 Glycogen phosphorylase Glycogen B6 Glyceraldehyde 3-P Glyceraldehyde 3-P DH 1,3 Bisphosphoglycerate B3 B1 B2 B3 B5 B7 Pyruvate carboxylase B2 B5 fumarate Succinate DH isocitrate B3 isocitrate DH B6 B1 B3 Matching: B1 B2 B3 B5 B6 B12 Vitamin C pantothenic acid cobalamin riboflavin ascorbic acid niacin thiamine pyridoxine Disease MC S/S or distinguishing S/S B1 Beriberi (deficiency) Wet- edema B2 Riboflavin deficiency Dermatitis, cheilosis, lacrimation B3 Pellagra (deficiency) 3 Ds: dematitis, diarrhea, dementia; Casal’s necklace B5 Pantothenic acid deficiency rare B6 Pyridoxine deficiency converts Trp to niacin Iron-loading microcytic anemia; Pellagra if no B3 made B7 Biotin deficiency (carboxylase rxns) Antibiotics / sulfonamides; seborrheic dermatitis B9 Folate deficiency Neural tube defects; megaloblasticmacrocytic anemia B12 Pernicious anemia (deficiency) – requires Castle’s intrinsic factor megaloblastic macrocytic anemia Beriberi Pernicious anemia –due to lack of Castle’s Intrinsic Factor Iron-loading microcytic anemia Scurvy Pellagra Megaloblasticmacrocytic anemia Thiamin deficiency Riboflavin deficiency Niacin deficiency Pantothenic acid deficiency Pyridoxine deficiency Biotin deficiency Folate deficiency Cobalamin deficiency Vitamin C deficiency Adult “wet” beriberi Adult “dry” beriberi Scurvy Pellagra Pernicious anemia Gingivitis, swollen joints & aching bones, delayed wound healing, muscle cramps, lassitude, dry and scaly skin Polyneuropathy, eye rigidity w/ nystagmus, muscle weakness, die of infection, no edema Due to lack of Castle’s Intrinsic Factor Edema, breathing difficulty, tachycardia, congestive heart failure Dermatitis, Diarrhea, Dementia Gingival hemorrhage bowed legs, stunted bone growth, and swollen joints. Infants fed only cow's milk are at risk of developing scurvy, since cow's milk is not an adequate source of vitamin C. periungual hemorrhage Typical rash AI for newborns: 40 mg/day RDA 75 mg/day for females 90 mg/day for males UL for adults: for adults: 2 g/day A daily intake of 200-300 mg would saturate the blood (1.2-1.5 mg/dL) Excess excreted in urine Anti-pernicious anemia factor FMN Pyridoxamine Vitamin B1 Vitamin B2 Riboflavin Vitamin B3 Nicotinic acid Vitamin B5 TPP Vitamin B6 CoASH Methylcobalamin Vitamin B7 Biotin Vitamin B9 Anti-pellagra factor Vitamin B12 Thiamin Vitamin C Pantothenic acid H4-folate Niacinamide Vitamin B1 Vitamin B2 Dehydroascorbic acid Vitamin B3 5’-deoxyadenosylcobalamin Vitamin B5 FAD Vitamin B6 NADP Vitamin B7 Anti-beriberi factor Pantetheine Vitamin B9 Folacin Vitamin B12 Pyridoxal phosphate Vitamin C Most important functions Vitamin A: Synthesis of rhodopsin, epithelial cell differentiation, bone growth and wound healing Vitamin D: Regulation of calcium levels (bone and blood) Vitamin E: Antioxidant Vitamin K: Activates blood-clotting factors Pro-vitamin A Carotenoids: α-carotene, β-carotene, γcarotene Most active Vitamin A vitamers Retinol, Retinal, Retinyl ester, Retinoic acid Non-vitamin A carotenoids Some carotenoids are not converted to vitamin A Drug form 13 cis-retinoic acid / all-trans retinoic acid (Accutane or Retin A) Retinol is stored in the liver as retinyl esters. If Question about retina (night blindness, etc): All trans-retinal 11-cis retinal If Question about differentiation, choose retinoic acid Uses: Dermatology, leukemia. It is a teratogen Food sources: Pro-vitamin A – think yellow/orange foods Retinyl ester (MC vitamer) – liver, fish, dairy eggs Mobilization: Retinol is bound to Retinol Binding Protein in the plasma Zn2+ is required for synthesis of RBP and for retinol binding RBP Symptoms: Eye lesions: Nyctalopia, xerophthalmia, Bitot’s spot, keratomalacia permanent blindness Epithelial disorders: Keratinization (toad skin), follicular hyperkeratosis, infections of eyes, ears, respiratory tract Reproductive failure Digestion: Diarrhea, decrease in appetite Pro-vitamin D Pre-vitamin D Vitamin D (2-step process in order to be usable) 1. UV-dependent: produces pre-form 2. Temperature dependent: makes vitamins D2 or D3 Equally active in humans Ergosterol Pre-D2 Ergocalciferol (vit D2) Occurs in yeast and some plants Ergo: fungus/mushrooms. Vitamin D2 is the form supplemented in MILK 7-dehydrocholesterol Pre-D3 cholecalciferol (vit D3) Occurs in human subcutaneous tissue Made from cholesterol Food Sources Fish, Egg yolk, Butter (fat/oil), Fortified foods: Milk, margarine, breakfast cereals, pastries, breads. Seasonal Vitamin D deficiency has been reported for people living in cold regions during the winter Humans can make only one fat soluble vitamin: Vitamin D3 Like all fat-soluble vitamins, Vitamin D is absorbed in the small intestine, bound to chylomicrons, and transported through the lymph. Endogenously synthesized vitamin D is bound to α-2-globulin (plasma protein) for transport Vitamin D is primarily stored in the liver. Mobilization of vitamin D, and conversion to its active form, occurs only when needed and is under hormonal regulation Vitamins D2 and D3 are stored in the liver as 25-hydroxy(chole/ergo)calciferol cholecalciferol hydroxylation 25-hydroxy-cholecalciferol hydroxylation Biochemically Active form 1,25-dihydroxy-cholecalciferol Effect of Vit D3 on Intestine and Kidney: ↑ synthesis of Calcium Binding Protein (calbindin) causing re-absorption of Ca and P from urine …To maintain serum calcium at optimal levels (~5 mM or 10 mg/dL) Effect of Vit D3 on Bone: Low serum calcium triggers PTH release. PTH stimulates 1-hydroxylase to form more 1,25(OH)2D, which at high concentration causes bone resorption releases Ca2+ to increase serum Ca2+ parathyroid 1,25(OH)2D3 kidney Self-regulation: (negative feedback): High 1,25(OH)2D stimulates 24-hydroxylase to make more active 24,25(OH)2D, instead of 1,25(OH)2D. parathyroid 1,25(OH)2D3 1,25(OH)2D2D 24,25(OH) 1,25(OH)23D23D 24,25(OH) 1,25(OH)23D23D kidney 24,25(OH) 1,25(OH)23D23D 24,25(OH) 24,25(OH)323D3 1. The only fat-soluble vitamin made by humans 2. Absorbed in sm. intestine chylomicron lymph blood liver (stored as 25-hydroxy D3) 3. Activated in liver by 1-hydroxylase (PTH) Inhibited by 24-hydroxylase (calcitonin) 4. Maintains serum calcium levels (reabsorbs from urine and takes from bone) Symptoms: Rickets in children: Bow legs, knock knees, rachitic rosary of ribs, pigeon chest, narrow pelvis, spinal curvature, skull deformation, muscle weakness, irritability, tetanus convulsion, poor teeth Osteomalacia in adults: Bow legs, bone fractures, pain in the bone of legs and lower back, walking difficulty, muscle weakness Also: Rachitic rosary “Hypervitaminosis D” hypercalcemia Signs/symptoms: Anorexia, Nausea, Vomiting Polyuria, Polydipsia Weakness, Nervousness Renal failure Calcification of soft tissues (joints, lung, kidneys, blood vessels, heart… can be fatal) Calcium comes from bone Food Sources: Fats and oils Vegetable oils: safflower, sunflower, soybean Dairy: Whole milk (in the fat) Meat / Fish: liver Grains and Fortified food: margarine Main Function Antioxidant: Neutralizes free radicals. Preserves membrane integrity, and fat soluble factors Found primarily in mitochondria. Absorption Passive absorption (no protein carrier) in the sm intestine Transported by chylomicron via lymph to the liver Transport First absorbed inside a chylomicron Packaged into HDLs, LDLs, and VLDLs α-tocopherol is selectively incorporated into VLDL, due to its high affinity for α-TTP (α-tocopherol transfer protein), accounting for its high biological activity. Storage Constituent of the membrane Primarily stored in adipose tissue Mobilized and transported by LDL, HDL and VLDL Deficiency is rare abundant in foods and well stored in the body Symptoms: Neurological: Areflexia, Cerebellar ataxia Loss of position sense, Loss of vibration sense, Muscle weakness Excess Prolonged bleeding time (anti vitamin K) May compete with vitamin A and D Vitamin E competes with the other fat-soluble vitamins Vitamin K is absorbed in the small intestine bound to chylomicrons and transported through lymph. Excessive intake of Ca2+ impairs vitamin K absorption Storage of vitamin K in the body is relatively low Perhaps due to continuous supply by the intestinal bacteria. Major storage is in liver Other sites: skin, muscle, kidney and heart Blood coagulation Converts blood coagulation factors II, VII, IX, X from pre-forms to pro-forms Prevents excessive blood coagulation Converts pre-C and pre-S proteins to C and S proteins… which destroy factors V and VIII when levels get too high Stimulates mineralization of bone and teeth γ carboxylation of osteocalcin (binds Ca2+ to bone & teeth) Maintains serum calcium levels by working with PTH to increase kidney re-absorption of Ca2+; the γ carboxylation of kidney glutamic protein (KGP) is stimulated by PTH Primary causes poor placental transfer from mother Lack of intestinal flora in newborn Hospital practice: inject 1 mg of K1 or synthetic K3 upon birth Secondary causes Use of antibiotics (may kill intestinal flora) Excessive anticoagulants (dicumarol, warfarin) Symptoms of deficiency: Impaired blood coagulation Prolonged bleeding Muscular and subcutaneous hemorrhage Impaired mineralization of bone and teeth Lipid foods increase fat-soluble vitamin absorption Vitamin A increases the number of receptors for 1,25(OH)2D, and enhances the action of vitamin D Adequate intake of protein and Zinc are essential for the mobilization of stored Vitamin A Mineralization of bone and teeth requires the simultaneous adequate intake of Vitamins A and D, Ca, P, Mg, Cl Vitamin E and Se are both anti-oxidants and enhance each other’s activity; they also spare vitamin A. Excessive intake of vitamin E antagonizes vitamins A, D, and K Vitamins 2:30 to answer all four 3. A deficient intake of vitamin __ 1. Which vitamin is NOT can develop pellagra because involved in lowering the blood level of homocysteine ___ is not converted to ____ a. Pyridoxine a. B6, glutamate, glutamine b. Riboflavin b. B2, riboflavin, FAD c. Folic acid c. B6, tryptophan, niacin d. Cobalamin d. B12, dUMP, dTMP 2. A patient with photophobia, 4. The “Methyl Folate Trap”, a lacrimation and cheilosis is condition of accumulation of most likely deficient in excessive methyl folate, is vitamin ___ caused by the deficiency of ___ a. Thiamin a. Cobalamin b. Riboflavin b. Folic acid c. Niacin d. Biotin c. Thiamin d. Niacin 2:00 to answer all four 7. A patient who has red, swollen 5. Glycolysis cannot occur gums and complains of bone without the coenzyme form of vitamin ______ pain may be deficient in a. Thiamin a. Vitamin B6 b. Riboflavin b. Cobalamin c. Niacin c. Folacin d. Biotin d. Ascorbic acid 6. Glutathione reductase is a flavoprotein because it possesses vitamin ____ in its structure a. B1 b. B2 c. B3 d. B6 8. Coenzyme A, which is needed for the metabolism of lipids is derived from a. Pantothenic acid b. Cobalamin c. Folacin d. Ascorbic acid 1:30 to answer all three 9. The primary cause of pernicious anemia is due to the deficiency of a. Vitamin B6 b. Cobalamin c. Folic acid d. Castle’s intrinsic factor 10. A patient with megaloblastic-macrocytic anemia may be deficient in a. Vitamin B1 or B2 b. Cobalamin of folic acid c. Vitamin B5 or B6 d. Vit C or Vitamin B6 11. Even with adequate dietary intake, alcoholics are most likely to be deficient in a. Vitamin A b. B vitamins c. Vitamin C d. Vitamin D 1:00 to answer both 12. The reason vitamin C is a good anti-oxidant is because a. It is a strong oxidant b. It is a strong reductant c. It is a strong acid d. It is a strong base 13. The coenzyme form of which one is NOT required for the conversion of pyruvate to acetyl-CoA in the use of glucose for energy a. Thiamine b. Riboflavin c. Niacin d. Biotin 2:30 to answer all four 16. Infantile desquamative 14. A man who complains of erythroderma can be numbness and tingling in his extremities, weakness and mental caused by deficiency of confusion might be suffering a. Vitamin B1 from a deficiency of b. Vitamin B2 a. Vitamin B1 c. Vitamin B3 b. Vitamin B2 c. Vitamin B3 d. Biotin d. Biotin 17. The coenzyme from of 15. Which vitamin listed is LEAST which one is not required likely to be related to health of for the Kreb’s cycle skin and other epithelial tissues a. Vitamin A a. Vitamin B5 b. B Vitamins b. Vitamin B2 c. Vitamin C c. Vitamin B3 d. Vitamin D d. Biotin 1:30 to answer all four Answer choices for all questions: a. FAD / FADH2 b. NAD+ / NADH + H+ c. CoASH d. Pyridoxal phosphate 18. Which one is derived from pantothenic acid? 19. Which one is derived from vitamin B6? 20. Which one is derived from riboflavin? 21. Which one is derived from nicotinamide? 1:00 to answer both 22. Thiamine pyrophosphate is the coenzyme form of which one a. Vitamin B1 b. Vitamin B2 c. Niacin d. Vitamin B6 23. The daily requirement of which one is proportional to the daily protein need because it is essential for amino acid metabolism a. Pantothenate b. Pyridoxine c. Cobalamin d. Folate 1. Which vitamin is NOT involved in lowering the blood level of homocysteine a. Pyridoxine b. Riboflavin c. Folic acid d. Cobalamin 3. A deficient intake of vitamin __ can develop pellagra because ___ is not converted to ____ a. B6, glutamate, glutamine b. B2, riboflavin, FAD c. B6, tryptophan, niacin d. B12, dUMP, dTMP 2. A patient with photophobia, 4. The “Methyl Folate Trap”, a lacrimation and cheilosis is condition of accumulation of most likely deficient in excessive methyl folate, is vitamin ___ caused by the deficiency of ___ a. Thiamin a. Cobalamin b. Riboflavin b. Folic acid c. Niacin d. Biotin c. Thiamin d. Niacin 5. Glycolysis cannot occur without the coenzyme form of vitamin ______ a. Thiamin b. Riboflavin c. Niacin d. Biotin 7. A patient who has red, swollen gums and complains of bone pain may be deficient in a. Vitamin B6 b. Cobalamin c. Folacin d. Ascorbic acid 6. Glutathione reductase is a flavoprotein because it possesses vitamin ____ in its structure a. B1 b. B2 c. B3 d. B6 8. Coenzyme A, which is needed for the metabolism of lipids is derived from a. Pantothenic acid b. Cobalamin c. Folacin d. Ascorbic acid 9. The primary cause of pernicious anemia is due to the deficiency of a. Vitamin B6 b. Cobalamin c. Folic acid d. Castle’s intrinsic factor 10. A patient with megaloblastic-macrocytic anemia may be deficient in a. Vitamin B1 or B2 b. Cobalamin of folic acid c. Vitamin B5 or B6 d. Vit C or Vitamin B6 11. Even with adequate dietary intake, alcoholics are most likely to be deficient in a. Vitamin A b. B vitamins c. Vitamin C d. Vitamin D 12. The reason vitamin C is a good anti-oxidant is because a. It is a strong oxidant b. It is a strong reductant c. It is a strong acid d. It is a strong base 13. The coenzyme form of which one is NOT required for the conversion of pyruvate to acetyl-CoA in the use of D-glucose for energy a. Thiamine b. Riboflavin c. Niacin d. Biotin 16. Infantile desquamative 14. A man who complains of erythroderma can be numbness and tingling in his extremities, weakness and mental caused by deficiency of confusion might be suffering a. Vitamin B1 from a deficiency of b. Vitamin B2 a. Vitamin B1 c. Vitamin B3 b. Vitamin B2 c. Vitamin B3 d. Biotin d. Biotin 17. The coenzyme from of 15. Which vitamin listed is LEAST which one is not required likely to be related to health of for the Kreb’s cycle skin and other epithelial tissues a. Vitamin A a. Vitamin B5 b. B Vitamins b. Vitamin B2 c. Vitamin C c. Vitamin B3 d. Vitamin D d. Biotin Answer choices for all questions: a. FAD / FADH2 b. NAD+ / NADH + H+ c. CoASH d. Pyridoxal phosphate 18. C 19. D 20. A 21. B Which one is derived from pantothenic acid? Which one is derived from vitamin B6? Which one is derived from riboflavin? Which one is derived from nicotinamide? 22. Thiamine pyrophosphate is the coenzyme form of which one a. Vitamin B1 b. Vitamin B2 c. Niacin d. Vitamin B6 23. The daily requirement of which one is proportional to the daily protein need because it is essential for amino acid metabolism a. Pantothenate b. Pyridoxine c. Cobalamin d. Folate Factors Physiologic needs increasing absorption Pregnancy, lactation Growth Phlebotomy Menstruation, chronic bleeding Iron form (e.g. heme, Fe3+) Ascorbic acid (vitamin C) and low pH enhance absorption by favoring Fe2+ over Fe3+ Best absorbed as heme, as found in hemoglobin and myoglobin Newborn 0.27 mg/day Adult males 8 mg/day Adult females 19-50 18 mg/day Adult females 51+ 8 mg/day Pregnancy 27 mg/day AI Adults: 3.8 grams of table salt (1 tsp) 1.5 g of Na 2.3 g Cl UL: 5.8 grams of table salt People consume salt in excess of UL Mineral Function Calcium Hydroxyapatite; cellular regulation Phosphorus Hydroxyapatite; osmotic balance; ATP, phospholipids, and other phosphate-containing molecules Magnesium Enzyme cofactor or activator, especially for energy extraction (think ATP) and RNA related enzymes Sodium Electrolyte for nerve and muscle; glucose absorption; regulates blood pressure Potassium Potassium Electrolyte for nerve and muscle; protein synthesis; metabolism of carbohydrate (pyruvate kinase); raise pH; reduce bone loss Chloride Gastric acid formation; cofactor for α-amylase Sulfur Amino acid function (part of Cys & Met); Vitamin function (component of thiamine, biotin and pantothenic acid); Structure of connective tissue (component of some GAGs e.g. heparin); Bile function (taurocholic acid) Iron Hemoglobin, myoglobin, heme-containing enzymes, nonheme iron-containing enzyme Mineral Function Copper Ceruloplasmin component, e.g., iron uptake in red marrow; Connective tissue development through collagen cross linking Zinc Cofactor and component of metalloproteins… think vitamin A and insulin Iodine Thyroid hormones (T4 and T3) and BMR setting Manganese Sphingosine synthesis; Carb metabolism, superoxide dismutase Fluoride Hard tissue mineral, (fluoroapatite), anti-cariogenic (cavity) Molybdenum Uric acid Selenium Antioxidant / enzyme component (glutathione peroxidase) Chromium Increased insulin function; Increases HDL, lowers LDL Cobalt Vitamin B12 synthesis Boron Role in bone DEFICIENCY Excess Fe ↑TIBC & ↑transferrin Chronic fatigue, headache, pallor, infection, Depression ↑transferrin Hemosiderosis Hemochromatosis Cu Menke’s dz: Steely hair, diarrhea, albinism, nerve degeneration Wilson’s dz: MR, tremor, Kayser-Fleischer ring Zn Acrodermatitis enteropathica: (Genetic) ↓absorporption Vomit, diarrhea, abdominal cramps I Simple goiter, cretinism, deafmute, motor rigidity Iodide goiter, Hyperactivity F Tooth decay Fluorosis: Mottled teeth, black bone Se Keshan dz: white nail beds, Anemia Cirrhosis, splenomegaly, GI bleeding, depression, dental caries Minerals 45 sec to answer both 1. Which nutritional abnormality is NOT associated with hypertension a. Excess of sodium b. Sodium deficiency c. Deficiency of potassium d. Deficiency of calcium 2. The deficiency of which one would NOT impair the body’s ability to remove superoxide a. Copper b. Zinc c. Manganese d. Fluoride 45 sec to answer both 3. Thyroid goiter could be caused by a. Iodine deficiency b. Iodine excess c. Manganese deficiency d. Both ‘a’ and ‘b’ 4. Which is NOT known to be critical to bone a. Calcium b. Phosphate c. Boron d. Potassium 1:00 to answer all three 5. The ionic form of which one is a common cofactor for kinases a. Calcium b. Magnesium c. Sodium d. Potassium 6. Hemosiderosis is due to the toxicity of which one a. Iron b. Copper c. Zinc d. Iodine 7. Dark brown chalk-like powder on the surface of teeth could be due to toxicity a. F b. Se c. Cr d. B 1:30 to answer all three 8. Which of the following is toxic to the electron transport chain, but a trace amount is also needed by humans a. Potassium b. Lead c. Arsenic d. Aluminum 9. Excessive intake of which one is teratogenic in birds and humans, and increases the risk of mental retardation and learning disability a. Na b. K c. Se d. Ca 10. The organic form of Se is selenomethionine which occurs in_____ a. Glutathione reductase b. Glutathione peroxidase c. Glutathione transhydrogenase d. Glutathione transsulfurase 1. Which nutritional abnormality is NOT associated with hypertension a. Excess of sodium b. Sodium deficiency c. Deficiency of potassium d. Deficiency of calcium 2. The deficiency of which one would NOT impair the body’s ability to remove superoxide a. Copper b. Zinc c. Manganese d. Fluoride 3. Thyroid goiter could be caused by a. Iodine deficiency b. Iodine excess c. Manganese deficiency d. Both ‘a’ and ‘b’ 4. Which is NOT known to be critical to bone a. Calcium b. Phosphate c. Boron d. Potassium 5. The ionic form of which one is a common cofactor for kinases a. Calcium b. Magnesium c. Sodium d. Potassium 6. Hemosiderosis is due to the toxicity of which one a. Iron b. Copper c. Zinc d. Iodine 7. Dark brown chalk-like powder on the surface of teeth could be due to toxicity a. F b. Se c. Cr d. B 8. Which of the following is toxic to the electron transport chain, but a trace amount is also needed by humans a. Potassium b. Lead c. Arsenic d. Aluminum 9. Excessive intake of which one is teratogenic in birds and humans, and increases the risk of mental retardation and learning disability a. Na b. K c. Se d. Ca 10. The organic form of Se is selenomethionine which occurs in_____ a. Glutathione reductase b. Glutathione peroxidase c. Glutathione transhydrogenase d. Glutathione transsulfurasea 1. Adrenaline (catecholamine made from tyrosine) What you should know: If a pathway produces energy (or molecules used to produce energy), epinephrine stimulates it If a pathway stores energy, epinephrine inhibits it 2. Thyroxin: (also from tyrosine) Increases the BMR by elevating enzyme activity Liver and muscle mostly affected 1. Pituitary hormones: Anterior: GH, prolactin, TSH, ACTH, FSH, LH Posterior: oxytocin and ADH 2. Insulin: If a pathway stores energy or molecules used for energy, insulin stimulates it It inhibits Hormone-sensitive lipase Diabetes mellitus due to insufficient insulin (Type I) or non-functional insulin receptors (Type II) 3. Glucagon: opposes insulin Stimulates glycogenolysis (same as epinephrine) but does not increase glycolysis or stimulate Σ nervous system therefore glucose is released to blood 4. Somatostatin (secreted by hypothalamus): It inhibits secretion of GH, TSH, ACTH, cholecystokinin, insulin and glucagon Although formed in different tissues due to different sets of enzymes, all are formed from cholesterol Cholesterol is mainly derived from blood plasma, some is from intracellular synthesis For all steroid hormones, the first enzyme is cholesterol desmolase (P-450scc) which cleaves the side-chain of cholesterol (missing this enzyme is fatal) All steroid hormones are produced by adrenal cortex Gonado-corticoids are also produced by sex organs How all steroid hormones work They bind receptors nucleus binds DNA alters rate of RNA synthesis affects amount of proteins / enzymes Glucocorticoids One important physiological function is the stimulation of gluconeogenesis from proteins. Examples: cortisol (hydrocortisone) and corticosterone Synthesized in the adrenal cortex. Effect on carbohydrates Gluconeogenesis (Insulin opposes) Induce liver enzymes involved in use of amino acids for gluconeogenesis Glycogenesis Increases protein phosphatase (which converts glycogen synthase from b-form to a-form) Effect on lipids Lipolysis Lipogenesis In extremities In face and trunk Effect on protein Hepatic protein synthesis Extrahepatic catabolism Presumably to provide more amino acids for gluconeogenesis Cushing’s Syndrome: Glucocorticoid excess due to excessive pharmacologic doses, adrenal carcinoma, excessive ACTH from pituitary adenoma Mineralocorticoids Enhance Na+ retention enhance excretion of K+, H+, NH4+. The primary endogenous mineralocorticoid is aldosterone Conn’s Syndrome: Primary aldosteronism Raised aldosterone levels due to adenoma of glomerulosa cells (synthesizing aldosterone) Addison’s Disease: Primary adrenal insufficiency Generalized skin pigmentation (white patient) Gums, nails, palmer creases Secondary Adrenal Insufficiency: Due to ACTH deficiency Adrenal hormones Cortisol and corticosterone glucocorticoids Aldosterone mineralocorticoid Congenital Adrenal Hyperplasia (Adrenogenital Syndrome) A group of conditions affecting cortisol production. Often involve greater or lesser production of sex steroids and can alter development sex characteristics in affected people A small minority of people can be said to be hermaphrodites Deficiency of P-450scc (cholesterol desmolase) Deficiency can be fatal Reproductive Steroids (gonadocorticoids) Androgens (Male sex steroids) Primarily produced by testes. Examples: testosterone and dihydrotestosterone (DHT). Testes also make some 17β-estradiol (estrogen) Estrogens (Female sex steroids) Primarily produced by ovaries. Examples: 17βestradiol (estrogen) and estrone Progestins (Gestational steroids) Produced by corpus luteum and placenta. Example: Progesterone Biochemical effects Sexual differentiation Spermatogenesis Anabolic metabolism Male-pattern behavior Biosynthesis Conversion of testosterone to DHT can occur in testes and other tissues (e.g. muscle). Conversion is a NADPH-dependent reduction by 5-α-reductase. DHT is the most active androgen Biochemical effects Maturation of primordial germ cells Develop uterine tissues for implantation of blastocyst Regulation of ovulation Establish condition of pregnancy (w/ placental hormones) Effect of parturation and lactation Biosynthesis Synthesized from androgens by the action of aromatase. Insulin opposes Glucagon/Epinephrine Increases entry of glucose and neutral amino acids into target cells Increases protein synthesis in skeletal muscle Increases glycolysis (activates glucokinase, PFK-1) Decrease gluconeogenesis (inactivates PEPCK gene) Increases glycogenesis (activates glycogen synthase) Decreases glycogenolysis (inactivates glycogen phosphorylase) Increases lipogenesis (activates acetyl-CoA carboxylase) Decreases lipolysis (inactivates hormone-sensitive lipase) IgG antibody stimulates the thyroid Activates the TSH receptor Diffuse hypertrophy of the thyroid gland Uncontrollable production of T3 and T4 In response, the body decreases TSH Hormones 2:00 to answer all four Answer choices for all questions: a. Niemann-Pick disease b. Multiple sclerosis c. Addison’s Disease d. Conn’s Syndrome 1. Which one is associated with the deficiency of phospholipids and sphingolipids in white matter? 2. Which one is due to the deficiency of sphingomyelinase, an enzyme responsible for the catabolism of sphingomyelins? 3. Hypernatremia and hypokalemia are associated with which one because of the excessive synthesis of aldosterone? 4. Impaired gluconeogenesis or hypoglycemia occur in which one? 1:00 to answer all four Answer choices for all questions: a. Cortisol b. Androgen c. Estrogen d. Progestin 5. Dihydrotestosterone is the most potent form of which one? 6. Which one is an aromatic steroid? 7. Anabolic steroids are analogues of which one? 8. Which one can increase the liver levels of alanine aminotransferase and PEP carboxykinase? 1:30 to answer all three Answer choices for all questions: a. Desaturase b. PEP-carboxykinase c. Glycogen synthase d. Aromatase 9. Glucocorticoids can stimulate gluconeogenesis by increasing the liver of which one? 10. Which one is abundant in ovaries and is responsible for the conversion of androgens to estrogens? 11. Which one catalyzes the synthesis of certain unsaturated fatty acids from saturated fatty acids? 1:30 to answer all three Answer choices for all questions: a. Cortisol b. Aldosterone c. Dihydrotestosterone d. 17-β-estradiol 12. Conn’s Syndrome is characterized by hypernatremia, hypertension and hypokalemia, and is due to excessive production of which one? 13. Anabolic steroids are structural analogues of which one? 14. Which one has the strongest anti-inflammatory action? 1:30 to answer all three Answer choices for all questions: a. Acetyl-CoA carboxylase b. Carnitine-palmitoyltransferase I c. HMG-CoA reductase d. Desaturase 15. Insulin increases the activity of which one? 16. Epinephrine & glucagon suppress the activity of which one? 17. A high body level of cholesterol reduces the activity of which one, (a way to regulate body cholesterol level)? Answer choices for all questions: a. Niemann-Pick disease b. Multiple sclerosis c. Addison’s Disease d. Conn’s Syndrome 1. Which one is associated with the deficiency of phospholipids and sphingolipids in white matter? B 2. Which one is due to the deficiency of sphingomyelinase, an enzyme responsible for the catabolism of sphingomyelins? A 3. Hypernatremia and hypokalemia are associated with which one because of the excessive synthesis of aldosterone? D 4. Impaired gluconeogenesis or hypoglycemia occur in which one? C Answer choices for all questions: a. Cortisol b. Androgen c. Estrogen d. Progestin 5. Dihydrotestosterone is the most potent form of which one? B 6. Which one is an aromatic steroid? C 7. Anabolic steroids are analogues of which one? B 8. Which one can increase the liver levels of alanine A aminotransferase and PEP carboxykinase? Answer choices for all questions: a. Desaturase b. PEP-carboxykinase c. Glycogen synthase d. Aromatase 9. Glucocorticoids can stimulate gluconeogenesis by increasing the liver of which one? B 10. Which one is abundant in ovaries and is responsible for the conversion of androgens to estrogens? D 11. Which one catalyzes the synthesis of certain unsaturated fatty acids from saturated fatty acids? A Answer choices for all questions: a. Cortisol b. Aldosterone c. Dihydrotestosterone d. 17-β-estradiol 12. Conn’s Syndrome is characterized by hypernatremia, B hypertension and hypokalemia, and is due to excessive production of which one? C 13. Anabolic steroids are structural analogues of which one? A 14. Which one has the strongest anti-inflammatory action? Answer choices for all questions: a. Acetyl-CoA carboxylase b. Carnitine-palmitoyltransferase I c. HMG-CoA reductase d. Desaturase 15. Insulin increases the activity of which one? A 16. Epinephrine & glucagon suppress the activity of which one? A 17. A high body level of cholesterol reduces the activity of C which one, (a way to regulate body cholesterol level)?