
Solutions to 7.014 Problem Set 1
... iii) Is the primary structure of the 50 kD protein the same or different than the primary structure of the 250 kD protein? Explain briefly. The primary structure is the same. The linear sequence of amino acids is the same. ...
... iii) Is the primary structure of the 50 kD protein the same or different than the primary structure of the 250 kD protein? Explain briefly. The primary structure is the same. The linear sequence of amino acids is the same. ...
A STUDY OF THE ROLES OF SELECTED ARGININE AND
... the process is a very complex and thus requires a balance between clot formation (coagulation) and clot dissolution (fibrinolysis) (Figure 1-1). If the balance shifts toward coagulation, thrombotic events such as heart attack or stroke may occur. On the other hand, if the balance shifts toward fibri ...
... the process is a very complex and thus requires a balance between clot formation (coagulation) and clot dissolution (fibrinolysis) (Figure 1-1). If the balance shifts toward coagulation, thrombotic events such as heart attack or stroke may occur. On the other hand, if the balance shifts toward fibri ...
Allelic Amino Acid Substitutions Affect the
... have been described, often only in heterozygous combinations because of their low allelic frequency (3). The two most common PLAP phenotypes, S (slow) and F (fast), differ only in an Arg#{176} to p2o9 substitution (4), but additional amino acid replacements have been identified for the I (intermedia ...
... have been described, often only in heterozygous combinations because of their low allelic frequency (3). The two most common PLAP phenotypes, S (slow) and F (fast), differ only in an Arg#{176} to p2o9 substitution (4), but additional amino acid replacements have been identified for the I (intermedia ...
Metabolic downregulation during diapause in embryos of Artemia
... metabolic depression achieved. In order to withstand such environmental challenges, it is crucial to depress both energy consuming and energy producing pathways. Otherwise it is possible that cellular energy reserves would be depleted and the organism will reach an energetic state from which recover ...
... metabolic depression achieved. In order to withstand such environmental challenges, it is crucial to depress both energy consuming and energy producing pathways. Otherwise it is possible that cellular energy reserves would be depleted and the organism will reach an energetic state from which recover ...
Pyruvate dehydrogenase - Wageningen UR E
... 1984b; Packman & Perham, 1987; Chuang, 1985;Hanemaaijer et al., 1987].From N- to Cterminus it contains two or three lipoyl domains (dependent on the type and source of the complex), an E1/E3 binding domain and a catalytic domain. NMR experiments indicate that the linker sequences are extended and hi ...
... 1984b; Packman & Perham, 1987; Chuang, 1985;Hanemaaijer et al., 1987].From N- to Cterminus it contains two or three lipoyl domains (dependent on the type and source of the complex), an E1/E3 binding domain and a catalytic domain. NMR experiments indicate that the linker sequences are extended and hi ...
REGULATION OF CYTOCHROME P450 BY
... of structures should provide a better understanding of the substrate selectivity and unusual kinetics of this important enzyme. Finally, a structure for P450 2A6 has been reported in a meeting abstract (Yano et al,, 2004b), Humans express 57 putatively functional genes and 58 pseudogenes (Nelson et ...
... of structures should provide a better understanding of the substrate selectivity and unusual kinetics of this important enzyme. Finally, a structure for P450 2A6 has been reported in a meeting abstract (Yano et al,, 2004b), Humans express 57 putatively functional genes and 58 pseudogenes (Nelson et ...
Elucidation and Modulation of CEB Metabolism in Fischer 344 Rats
... activity towards some xenobiotic. The liver receives blood from the splanchnic area which contains not only nutrients but various foreign substances, or xenobiotics, as well. These compounds are metabolized by the liver prior to release into the systemic circulation. Other tissues involved in biotra ...
... activity towards some xenobiotic. The liver receives blood from the splanchnic area which contains not only nutrients but various foreign substances, or xenobiotics, as well. These compounds are metabolized by the liver prior to release into the systemic circulation. Other tissues involved in biotra ...
STUDIES ON THE CHLORAMPHENICOL HALOGENASE CmlS
... for the regio- and stereoselective incorporation of halogens into natural products. These enzymes require FAD, O2, NADH, and a flavin reductase to perform catalysis. The majority of these enzymes are observed to catalyze the halogenation of aromatic substrates. CmlS is a unique member of the flavin- ...
... for the regio- and stereoselective incorporation of halogens into natural products. These enzymes require FAD, O2, NADH, and a flavin reductase to perform catalysis. The majority of these enzymes are observed to catalyze the halogenation of aromatic substrates. CmlS is a unique member of the flavin- ...
Midazolam Oxidation by Cytochrome P450 3A4 and Active
... Ala-305, Tyr-307, and Thr-309 with a smaller amino acid decreased this ratio. Kinetic analyses of nine key mutants revealed that the alteration in regioselectivity is caused by a change in kinetic parameters (Vmax and KM) for the formation of both metabolites in most cases. The study revealed the ro ...
... Ala-305, Tyr-307, and Thr-309 with a smaller amino acid decreased this ratio. Kinetic analyses of nine key mutants revealed that the alteration in regioselectivity is caused by a change in kinetic parameters (Vmax and KM) for the formation of both metabolites in most cases. The study revealed the ro ...
Investigating the Porphyrias Through Analysis of
... A thesis submitted in partial fulfilment of the requirements for the Degree ...
... A thesis submitted in partial fulfilment of the requirements for the Degree ...
Mechanism of Posttranslational Regulation of Phenol
... activity (11, 12) catalyzed by β-form PST, and the R-form activity was mostly ignored (15, 16). The role of the two enzyme forms in physiological condition is yet to be studied. Complete conversion of the two enzyme forms has not been achieved previously in vitro. Part of the physiological activity ...
... activity (11, 12) catalyzed by β-form PST, and the R-form activity was mostly ignored (15, 16). The role of the two enzyme forms in physiological condition is yet to be studied. Complete conversion of the two enzyme forms has not been achieved previously in vitro. Part of the physiological activity ...
Biomimetic Reactions Catalyzed by Cyclodextrins and
... p-nitro, the accelerations were also smaller.85 This reflected a fundamental problem with rigid esterssthe oxygen atom of the nucleophilic hydroxyl group must attack perpendicular to the ester group plane but end up as part of the new ester, in the ester plane (Figure 3).86 The rotation needed to co ...
... p-nitro, the accelerations were also smaller.85 This reflected a fundamental problem with rigid esterssthe oxygen atom of the nucleophilic hydroxyl group must attack perpendicular to the ester group plane but end up as part of the new ester, in the ester plane (Figure 3).86 The rotation needed to co ...
The Effect of Thalidomide on Oxidation of Midazolam, S
... concentrations in the presence of various concentrations of thalidomide. 16 Thalidomide only had a small effect on the midazolam hydroxylation activities of P450 3A4 (Figure 11A). On the other hand, in the presence of thalidomide, midazolam 1'-hydroxylation activities of P450 3A5 at low substrate co ...
... concentrations in the presence of various concentrations of thalidomide. 16 Thalidomide only had a small effect on the midazolam hydroxylation activities of P450 3A4 (Figure 11A). On the other hand, in the presence of thalidomide, midazolam 1'-hydroxylation activities of P450 3A5 at low substrate co ...
Sample pages 1 PDF
... Early stages of the reaction, the optical purity of the product is mainly determined by the selectivity (a) of the first reaction step, which constitutes an enantiotopos or enantioface differentiation, depending on the type of substrate. As the reaction proceeds, the second hydrolytic step, being a ...
... Early stages of the reaction, the optical purity of the product is mainly determined by the selectivity (a) of the first reaction step, which constitutes an enantiotopos or enantioface differentiation, depending on the type of substrate. As the reaction proceeds, the second hydrolytic step, being a ...
Molecular and biochemical characterization of cytosolic
... interconversion of glucose 1-phosphate (G1P) and glucose 6-phosphate (G6P), with glucose 1,6-bisphosphate (G16BP) being a cofactor in this reaction (Ray et al., 1983). In plant tissues, PGM is present in the cytosol and the plastid (MuÈhlbach and Schnarrenberger, 1978; Sangwan and Singh, 1987; Popov ...
... interconversion of glucose 1-phosphate (G1P) and glucose 6-phosphate (G6P), with glucose 1,6-bisphosphate (G16BP) being a cofactor in this reaction (Ray et al., 1983). In plant tissues, PGM is present in the cytosol and the plastid (MuÈhlbach and Schnarrenberger, 1978; Sangwan and Singh, 1987; Popov ...
Biochemical characterization of the initial steps of the Kennedy
... and GPEtn in T. brucei, disruption of their biosynthetic pathways is likely to interfere with the parasite biology in multiple ways and thus the enzymes involved become of interest as possible novel targets for chemotherapy. Indeed, it has been proposed that the mode of action of lysophospholipid an ...
... and GPEtn in T. brucei, disruption of their biosynthetic pathways is likely to interfere with the parasite biology in multiple ways and thus the enzymes involved become of interest as possible novel targets for chemotherapy. Indeed, it has been proposed that the mode of action of lysophospholipid an ...
Advances in Environmental Biology
... profile can be used in floral authentication for certain floral honeys. Same as phenolic compounds, flavonoids also have a significant relation to the antioxidant capacity of honey [23]. From the result, generally, the total flavonoid content of Melaleuca honey was not high which around 12% of the t ...
... profile can be used in floral authentication for certain floral honeys. Same as phenolic compounds, flavonoids also have a significant relation to the antioxidant capacity of honey [23]. From the result, generally, the total flavonoid content of Melaleuca honey was not high which around 12% of the t ...
Functional and Biochemical Analysis of Glucose-6
... (GST)/G6PD fusion protein in Escherichia coli; and observed that the values of kinetic parameters from the biochemical characterization of the resulting proteins were the same as those reported using the initial vectors. These results revealed that this new system was very useful for the expression ...
... (GST)/G6PD fusion protein in Escherichia coli; and observed that the values of kinetic parameters from the biochemical characterization of the resulting proteins were the same as those reported using the initial vectors. These results revealed that this new system was very useful for the expression ...
Lecture 33 - University of Arizona
... homodimer that catalyzes a phosphorolysis cleavage reaction of the α1,4 glycosidic bond at the nonreducing ends of the glycogen molecule. Inorganic phosphate (Pi) attacks the glycosidic oxygen using an acid catalysis mechanism that releases glucose-1P as the product. ...
... homodimer that catalyzes a phosphorolysis cleavage reaction of the α1,4 glycosidic bond at the nonreducing ends of the glycogen molecule. Inorganic phosphate (Pi) attacks the glycosidic oxygen using an acid catalysis mechanism that releases glucose-1P as the product. ...
Polynucleotide Phosphorylase and Mitochondrial
... of the mitochondrial suspension was determined by means of the biuret method (Gornall et al., 1949) and usually was 90–100 mg/ml. Depletion of mitochondrial GSH. Procedures published by others (Han et al., 2003; Jocelyn and Cronshaw, 1985) were adapted to deplete mitochondria of GSH with CDNB. Brief ...
... of the mitochondrial suspension was determined by means of the biuret method (Gornall et al., 1949) and usually was 90–100 mg/ml. Depletion of mitochondrial GSH. Procedures published by others (Han et al., 2003; Jocelyn and Cronshaw, 1985) were adapted to deplete mitochondria of GSH with CDNB. Brief ...
Glycerol transport and phosphoenolpyruvate
... and metabolism independent of PTS-mediated activation by phosphorylation. This could indeed be confirmed for the His-232-Arg mutant glycerol kinase of Ent. casseliflavus, which exhibited much higher activity than the wild-type enzyme (Charrier et al., 1997). An amino acid sequence comparison with kn ...
... and metabolism independent of PTS-mediated activation by phosphorylation. This could indeed be confirmed for the His-232-Arg mutant glycerol kinase of Ent. casseliflavus, which exhibited much higher activity than the wild-type enzyme (Charrier et al., 1997). An amino acid sequence comparison with kn ...
Purification and Characterization of Chorismate
... sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified chorismate synthase is associated with an NADPH-dependent flavin mononucleotide reductase that provides in vivo the reduced flavin necessary for catalytic activity. In vitro, flavin reduction can be mediated by either dithionite or ...
... sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified chorismate synthase is associated with an NADPH-dependent flavin mononucleotide reductase that provides in vivo the reduced flavin necessary for catalytic activity. In vitro, flavin reduction can be mediated by either dithionite or ...
Temperature-dependent effects of cadmium and purine nucleotides
... Inhibition of invertebrate mitochondrial aconitase (Roesijadi, 1996) (A. S. Cherkasov, S. Grewal and I. M. Sokolova, manuscript submitted for publication). Thus, a combination of temperature and Cd stress is an environmentally relevant situation for populations of intertidal poikilotherms (includin ...
... Inhibition of invertebrate mitochondrial aconitase (Roesijadi, 1996) (A. S. Cherkasov, S. Grewal and I. M. Sokolova, manuscript submitted for publication). Thus, a combination of temperature and Cd stress is an environmentally relevant situation for populations of intertidal poikilotherms (includin ...
The Role of N- and C-terminal Amino Acids to
... The fundamental link between the primary amino acid sequence and the functional protein has long been an area of interest with much still to be discovered. The goal of studying protein folding is to ultimately predict the folded structure and the function of a protein from its primary sequence. Anfi ...
... The fundamental link between the primary amino acid sequence and the functional protein has long been an area of interest with much still to be discovered. The goal of studying protein folding is to ultimately predict the folded structure and the function of a protein from its primary sequence. Anfi ...
Article The Evolution of Momordica Cyclic Peptides
... Precursors of Momordica Cyclic and Acyclic Peptides Polymerase chain reaction (PCR) of Momordica genomic DNA using the primers that amplified TIPTOP genes from Momordica cochinchinensis and M. sphaeroidea (Mylne et al. 2012) resulted in new TIPTOP genes from two Asian Momordica, that is, one from M. ...
... Precursors of Momordica Cyclic and Acyclic Peptides Polymerase chain reaction (PCR) of Momordica genomic DNA using the primers that amplified TIPTOP genes from Momordica cochinchinensis and M. sphaeroidea (Mylne et al. 2012) resulted in new TIPTOP genes from two Asian Momordica, that is, one from M. ...
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.