for students of the Faculty of Medicine
... During a ninhydrine reaction, the amino acid decarboxylates and deaminates, and the released ammonia is fixed with ninhydrine to form a violet-bluecoloured product. Other fragments of molecules of amino acids, fixed with the α-carbon, are called side chains or side substituents. They are marked wit ...
... During a ninhydrine reaction, the amino acid decarboxylates and deaminates, and the released ammonia is fixed with ninhydrine to form a violet-bluecoloured product. Other fragments of molecules of amino acids, fixed with the α-carbon, are called side chains or side substituents. They are marked wit ...
Enzyme Mechanisms - Illinois Institute of Technology
... some portion of the time in which a reaction is being monitored, the concentration of the enzyme-substrate complex is nearly constant. Thus in the general reaction E + S ES E + P where E is the enzyme, S is the substrate, ES is the enzyme-substrate complex (or "enzymeintermediate complex"), and ...
... some portion of the time in which a reaction is being monitored, the concentration of the enzyme-substrate complex is nearly constant. Thus in the general reaction E + S ES E + P where E is the enzyme, S is the substrate, ES is the enzyme-substrate complex (or "enzymeintermediate complex"), and ...
Biochemistry 1997 Baird
... al., 1996). This CA IV is 266 amino acids in length with N-terminal and C-terminal truncations to delete the leader signal peptide and the sequence required for the attachment of the GPI anchor, respectively. The molecular weight of the enzyme (Mr ) 29 800) was calculated from the amino acid sequenc ...
... al., 1996). This CA IV is 266 amino acids in length with N-terminal and C-terminal truncations to delete the leader signal peptide and the sequence required for the attachment of the GPI anchor, respectively. The molecular weight of the enzyme (Mr ) 29 800) was calculated from the amino acid sequenc ...
Glycogen storage diseases - Journal of Clinical Pathology
... glucosyl units to the action of phosphorylase. Thus the degradation of glycogen, like its synthesis, requires the sequential interaction of two distinct enzymes and results in the formation of glucose and of glucose 1-phosphate which can be used by the cells for their metabolic requirements. Not all ...
... glucosyl units to the action of phosphorylase. Thus the degradation of glycogen, like its synthesis, requires the sequential interaction of two distinct enzymes and results in the formation of glucose and of glucose 1-phosphate which can be used by the cells for their metabolic requirements. Not all ...
Pyruvic Acid and Formic Acid Metabolism in Sarcina
... 0.1 M-citric acid buffer at the required pH; 30 pmoles pyruvate (side arm); 2.1 mg. bacterial protein; total volume 2.8 ml.; 0.2 ml. 3 N-H,SO, in the second side arm; atmosphere air; temperature 30". For hydrogen production (H)Warburg flasks contained: 2 ml. 0.2 M-Na,HPO,/o-I M-citric acid buffer at ...
... 0.1 M-citric acid buffer at the required pH; 30 pmoles pyruvate (side arm); 2.1 mg. bacterial protein; total volume 2.8 ml.; 0.2 ml. 3 N-H,SO, in the second side arm; atmosphere air; temperature 30". For hydrogen production (H)Warburg flasks contained: 2 ml. 0.2 M-Na,HPO,/o-I M-citric acid buffer at ...
N-terminal portion acts as an initiator of the inactivation of pepsin at
... N-fragment, N-frag(A) and N-frag(B) mutants showed that individual mutations in the N-fragment mutant were not critical for the stabilization of pepsin. Both N-frag (A) and (B) mutants showed slight stabilization effects (B) and were similar in stability (A) to the wild-type while the N-frag mutant ...
... N-fragment, N-frag(A) and N-frag(B) mutants showed that individual mutations in the N-fragment mutant were not critical for the stabilization of pepsin. Both N-frag (A) and (B) mutants showed slight stabilization effects (B) and were similar in stability (A) to the wild-type while the N-frag mutant ...
The Three-dimensional Structure of 4-Hydroxybenzoyl
... proteins, both amino acid sequence analyses and structural investigations have been carried out on the enzymes from Pseudomonas sp. strain CBS3 (10, 11). From these studies, it is now known that the 4-chlorobenzoyl-CoA ligase belongs to a large family of enzymes which function primarily in thiol tem ...
... proteins, both amino acid sequence analyses and structural investigations have been carried out on the enzymes from Pseudomonas sp. strain CBS3 (10, 11). From these studies, it is now known that the 4-chlorobenzoyl-CoA ligase belongs to a large family of enzymes which function primarily in thiol tem ...
Glycolysis and Gluconeogenesis
... Control of Glycolysis Of what value is glycolysis for cells? provides energy in form of ATP provides building blocks for synthetic reactions Where are most control points found? enzymes that catalyze irreversible reactions ...
... Control of Glycolysis Of what value is glycolysis for cells? provides energy in form of ATP provides building blocks for synthetic reactions Where are most control points found? enzymes that catalyze irreversible reactions ...
Hydrolysis of a Series of Synthetic Peptide Substrates by the Human
... Shih et al., 1978, 1979; Ypma-Wong et al., 1987a, b) and may represent an ideal target enzyme for antiviral chemotherapy. By analogy, this is almost certainly true for the 3C proteins of all picornaviruses, including human rhinoviruses. However there have been relatively few comprehensive studies on ...
... Shih et al., 1978, 1979; Ypma-Wong et al., 1987a, b) and may represent an ideal target enzyme for antiviral chemotherapy. By analogy, this is almost certainly true for the 3C proteins of all picornaviruses, including human rhinoviruses. However there have been relatively few comprehensive studies on ...
Plant aromatic amino acid decarboxylases
... plant species results in a multiplicity of functionally diverse AAAD enzymes. A single AAAD annotation does not accurately represent the selection of activities and substrate specificities. This can be illustrated through our recent study of some predicted Drosophila and mosquito AAAD sequences. Res ...
... plant species results in a multiplicity of functionally diverse AAAD enzymes. A single AAAD annotation does not accurately represent the selection of activities and substrate specificities. This can be illustrated through our recent study of some predicted Drosophila and mosquito AAAD sequences. Res ...
Comparison of the Functional Differences for the Homologous Residues within... Carboxy Phosphate and Carbamate Domains of Carbamoyl Phosphate Synthetase
... carbamoyl phosphate from two molecules of MgATP, bicarbonate, and glutamine. It has been previously shown that the amino- and carboxy-terminal halves of the large subunit of this protein are homologous. A working model for the active site structure of the carboxy-terminal domain of the large subunit ...
... carbamoyl phosphate from two molecules of MgATP, bicarbonate, and glutamine. It has been previously shown that the amino- and carboxy-terminal halves of the large subunit of this protein are homologous. A working model for the active site structure of the carboxy-terminal domain of the large subunit ...
Mechanistic insights into the regulation of metabolic enzymes by
... enzyme activity. An example of this mechanism is provided by the study of ornithine transcarbamylase (OTC), a urea cycle enzyme that catalyzes the condensation of ornithine and car bamoyl phosphate into citrulline. Ornithine is the deamina tion product of arginine, whereas carbamoyl phosphate is t ...
... enzyme activity. An example of this mechanism is provided by the study of ornithine transcarbamylase (OTC), a urea cycle enzyme that catalyzes the condensation of ornithine and car bamoyl phosphate into citrulline. Ornithine is the deamina tion product of arginine, whereas carbamoyl phosphate is t ...
Caspaar Bijleveld and Math JH Geelen
... isotopic procedures can be employed with subcellular preparations when precautions are taken to avoid contamination of the samples with mitochondrial enzymes. In tissue preparations devoid of mitochondrial enzymes it is still somewhat difficult to measure accurately the enzyme activity by i4C02 fixa ...
... isotopic procedures can be employed with subcellular preparations when precautions are taken to avoid contamination of the samples with mitochondrial enzymes. In tissue preparations devoid of mitochondrial enzymes it is still somewhat difficult to measure accurately the enzyme activity by i4C02 fixa ...
Structure, catalytic activity and evolutionary relationships of 1
... Both ethylene and the enzymes of ethylene synthesis are subjects of intensive scientific investigation. The present review discusses structure, catalytic activity and evolutionary relationships of 1-aminocyclopropane-1-carboxylate synthase, identified for the first time in ripening tomato in 1979. T ...
... Both ethylene and the enzymes of ethylene synthesis are subjects of intensive scientific investigation. The present review discusses structure, catalytic activity and evolutionary relationships of 1-aminocyclopropane-1-carboxylate synthase, identified for the first time in ripening tomato in 1979. T ...
Thermodynamic and Biophysical Characterization of Cytochrome P450
... obtained at saturation with substrate or ligand, S, Et is the total enzyme concentration used, and Kd is the apparent dissociation constant for the substrate- or ligand-enzyme complex. Binding of azole drugs (ketoconazole, miconazole, econazole) was performed both using BioI in the form isolated fro ...
... obtained at saturation with substrate or ligand, S, Et is the total enzyme concentration used, and Kd is the apparent dissociation constant for the substrate- or ligand-enzyme complex. Binding of azole drugs (ketoconazole, miconazole, econazole) was performed both using BioI in the form isolated fro ...
Salcedo-SoraAndMcAul
... Antifolate chemotherapy has been deployed using inhibitors that target at least two enzymes of folate biosynthesis and usage pathways and usually work due to a synergistic effect.44 The most common of such combinations is a DHFR inhibitor and a DHPS inhibitor for the treatment of infectious diseases ...
... Antifolate chemotherapy has been deployed using inhibitors that target at least two enzymes of folate biosynthesis and usage pathways and usually work due to a synergistic effect.44 The most common of such combinations is a DHFR inhibitor and a DHPS inhibitor for the treatment of infectious diseases ...
12. Molecular Recognition: The Thermodynamics of
... 12.2. The value of KD corresponds to the concentration of ligand at which the protein is half saturated. The reason that the dissociation constant, KD, is more commonly referred to than the association constant, KA, is that the value of KD is equal in magnitude to the concentration of ligand at whic ...
... 12.2. The value of KD corresponds to the concentration of ligand at which the protein is half saturated. The reason that the dissociation constant, KD, is more commonly referred to than the association constant, KA, is that the value of KD is equal in magnitude to the concentration of ligand at whic ...
C H A P
... primers HP0739FW and HP0739BW, designed for the specific amplification of estV (including the upstream – 132 bp – and downstream – 166 bp – regions), and bearing the sequence for the restriction nucleases XbaI and PstI, respectively. Amplification by PCR was performed using Pfu polymerase and a Tm o ...
... primers HP0739FW and HP0739BW, designed for the specific amplification of estV (including the upstream – 132 bp – and downstream – 166 bp – regions), and bearing the sequence for the restriction nucleases XbaI and PstI, respectively. Amplification by PCR was performed using Pfu polymerase and a Tm o ...
Biological Radical Sulfur Insertion Reactions
... sulfane sulfur. The reaction proceeds via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue (Figure 6).12,13 A mechanism for this reaction has been established by elegants studies from D. Dean on NifS, a cysteine desulfurase from Azotobacter vinelandii ...
... sulfane sulfur. The reaction proceeds via the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue (Figure 6).12,13 A mechanism for this reaction has been established by elegants studies from D. Dean on NifS, a cysteine desulfurase from Azotobacter vinelandii ...
Amino Acid Degradation
... A deficiency in phenylalanine hydroxylase is responsible for the disease phenylkotonuria (PKU) which is caused by elevated concentrations of phenylalanine. Individuals with a deficiency in phenylalanine hydroxylase rely on a secondary catabolic pathway which in normal individuals is not used. In thi ...
... A deficiency in phenylalanine hydroxylase is responsible for the disease phenylkotonuria (PKU) which is caused by elevated concentrations of phenylalanine. Individuals with a deficiency in phenylalanine hydroxylase rely on a secondary catabolic pathway which in normal individuals is not used. In thi ...
Biochemistry2 2016 Lecture Glycogen Metabolism
... 3. PLP is covalently bound and functions in this reaction differently than in amino acid metabolism. The phosphoryl group will aid in the acid-base catalysis. ...
... 3. PLP is covalently bound and functions in this reaction differently than in amino acid metabolism. The phosphoryl group will aid in the acid-base catalysis. ...
- Wiley Online Library
... Alanine dehydrogenase from M. tuberculosis catalyses the reductive amination of pyruvate at physiological pH [12,13]. To demonstrate that the M. smegmatis enzyme shows similar pH dependence, activity measurements at various pHs (pH 7.0^10.2) were carried out. These analyses showed that the velocity ...
... Alanine dehydrogenase from M. tuberculosis catalyses the reductive amination of pyruvate at physiological pH [12,13]. To demonstrate that the M. smegmatis enzyme shows similar pH dependence, activity measurements at various pHs (pH 7.0^10.2) were carried out. These analyses showed that the velocity ...
Respiratory enzyme activity and regulation of respiration pathway in
... seedlings were transferred from anaerobic to aerobic conditions. Additionally, Hadži-Tašković Šukalović and Vuletić (2001) reported that ammonium deficiency can decrease the activities of TCA cycle enzymes in maize (Zea mays L) roots. Compared with the TCA cycle, studies on the anaerobic fermentatio ...
... seedlings were transferred from anaerobic to aerobic conditions. Additionally, Hadži-Tašković Šukalović and Vuletić (2001) reported that ammonium deficiency can decrease the activities of TCA cycle enzymes in maize (Zea mays L) roots. Compared with the TCA cycle, studies on the anaerobic fermentatio ...
Enzyme inhibitor
An enzyme inhibitor is a molecule that binds to an enzyme and decreases its activity. Since blocking an enzyme's activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used in pesticides. Not all molecules that bind to enzymes are inhibitors; enzyme activators bind to enzymes and increase their enzymatic activity, while enzyme substrates bind and are converted to products in the normal catalytic cycle of the enzyme.The binding of an inhibitor can stop a substrate from entering the enzyme's active site and/or hinder the enzyme from catalyzing its reaction. Inhibitor binding is either reversible or irreversible. Irreversible inhibitors usually react with the enzyme and change it chemically (e.g. via covalent bond formation). These inhibitors modify key amino acid residues needed for enzymatic activity. In contrast, reversible inhibitors bind non-covalently and different types of inhibition are produced depending on whether these inhibitors bind to the enzyme, the enzyme-substrate complex, or both.Many drug molecules are enzyme inhibitors, so their discovery and improvement is an active area of research in biochemistry and pharmacology. A medicinal enzyme inhibitor is often judged by its specificity (its lack of binding to other proteins) and its potency (its dissociation constant, which indicates the concentration needed to inhibit the enzyme). A high specificity and potency ensure that a drug will have few side effects and thus low toxicity.Enzyme inhibitors also occur naturally and are involved in the regulation of metabolism. For example, enzymes in a metabolic pathway can be inhibited by downstream products. This type of negative feedback slows the production line when products begin to build up and is an important way to maintain homeostasis in a cell. Other cellular enzyme inhibitors are proteins that specifically bind to and inhibit an enzyme target. This can help control enzymes that may be damaging to a cell, like proteases or nucleases. A well-characterised example of this is the ribonuclease inhibitor, which binds to ribonucleases in one of the tightest known protein–protein interactions. Natural enzyme inhibitors can also be poisons and are used as defences against predators or as ways of killing prey.