Modification of the Enzymatic Activity of Renin by
... effect of dialysis, an additional aliquot of plasma was acidified to pH 3.3 by dropwise addition of 1 N HC1, without dialysis. Plasma was incubated at this pH for 18 hours at 4°C and then at 32°C for 45 minutes. These samples were then adjusted to pH 7.4 by addition of 1 N NaOH and were again incuba ...
... effect of dialysis, an additional aliquot of plasma was acidified to pH 3.3 by dropwise addition of 1 N HC1, without dialysis. Plasma was incubated at this pH for 18 hours at 4°C and then at 32°C for 45 minutes. These samples were then adjusted to pH 7.4 by addition of 1 N NaOH and were again incuba ...
Localization and nucleotide specificity of Blastocystis succinyl‐CoA
... eukaryotes (Figs. S2 and S3). This inability to clearly resolve the position of the Blastocystis SCS subunits may result from a lack of a more comprehensive sampling of stramenopile and chromistan sequences. In both trees, alpha-proteobacteria are sister to eukaryotes, indicating the mitochondrial a ...
... eukaryotes (Figs. S2 and S3). This inability to clearly resolve the position of the Blastocystis SCS subunits may result from a lack of a more comprehensive sampling of stramenopile and chromistan sequences. In both trees, alpha-proteobacteria are sister to eukaryotes, indicating the mitochondrial a ...
Novel control of lactate dehydrogenase from the freeze
... posttranslational modification (PTM) of LDH as a mechanism influencing enzyme function/properties in response to the stresses of freezing and dehydration. PTMs can have strong effects on enzymes including altering activity, kinetic parameters, protein stability, protein–protein or subunit–subunit in ...
... posttranslational modification (PTM) of LDH as a mechanism influencing enzyme function/properties in response to the stresses of freezing and dehydration. PTMs can have strong effects on enzymes including altering activity, kinetic parameters, protein stability, protein–protein or subunit–subunit in ...
Saccharomyces cerevisiae Functional Expression and Stabilization of Horseradish Peroxidase by Directed Evolution in
... from waste waters (Nicell et al., 1993) have also been proposed. These diverse possibilities reflect the broad substrate specificity and high specific activity of the natural enzyme. However, actual commercial uses have been limited to the diagnostic arena due to a number of factors. One is the enzy ...
... from waste waters (Nicell et al., 1993) have also been proposed. These diverse possibilities reflect the broad substrate specificity and high specific activity of the natural enzyme. However, actual commercial uses have been limited to the diagnostic arena due to a number of factors. One is the enzy ...
Catalytic Mechanism and Regulation of Mammalian Adenylyl Cyclases
... domains are modeled based on homology to IIC2 homodimer crystal structure (Zhang et al., 1997b; Liu et al., 1997). ATP has been docked into the active site in the anticonformation observed in the P-site inhibitor complex (Tesmer et al., 1997), and two Mg21 ions are shown as observed for T7 polymeras ...
... domains are modeled based on homology to IIC2 homodimer crystal structure (Zhang et al., 1997b; Liu et al., 1997). ATP has been docked into the active site in the anticonformation observed in the P-site inhibitor complex (Tesmer et al., 1997), and two Mg21 ions are shown as observed for T7 polymeras ...
ESTUDIO DE LOS MECANISMOS DE INHIBICIÓN DE LA ACTIVIDAD CARNITINA PALMITOILTRANSFERASA 1
... Residues Conserved in Malonyl-CoA Inhibited Versus Noninhibited Carnitine-Choline Acyltransferases—An exhaustive analysis of the presence of residues shared by all the malonylCoA-regulated enzymes of the carnitine-choline acyltransferase family versus the malonyl-CoA nonregulated members of the same ...
... Residues Conserved in Malonyl-CoA Inhibited Versus Noninhibited Carnitine-Choline Acyltransferases—An exhaustive analysis of the presence of residues shared by all the malonylCoA-regulated enzymes of the carnitine-choline acyltransferase family versus the malonyl-CoA nonregulated members of the same ...
Characterization of the Two-Component, FAD-Dependent Monooxygenase SgcC That Requires Carrier Protein-Tethered
... similarities.17–19 The first class, or one-component monooxygenases, are single polypeptides that utilize FAD or FMN as a cofactor and require NADH or NADPH to initiate oxidation of substrates; thus, these monooxygenases have both flavin reductase and monooxygnease activity. The second class, or two ...
... similarities.17–19 The first class, or one-component monooxygenases, are single polypeptides that utilize FAD or FMN as a cofactor and require NADH or NADPH to initiate oxidation of substrates; thus, these monooxygenases have both flavin reductase and monooxygnease activity. The second class, or two ...
Raines, ChemRev 1998
... its integrity and solubility under drastic conditions: first, 0.25 N sulfuric acid at 5 °C, and then, pH 3.0 at 95-100 °C.84 The final step in this protocol calls for crystallization of the enzyme. The three-dimensional structure of RNase A is fully encoded by its amino acid sequence.85-89 This disc ...
... its integrity and solubility under drastic conditions: first, 0.25 N sulfuric acid at 5 °C, and then, pH 3.0 at 95-100 °C.84 The final step in this protocol calls for crystallization of the enzyme. The three-dimensional structure of RNase A is fully encoded by its amino acid sequence.85-89 This disc ...
Principles of BIOCHEMISTRY
... gluconeogenesis are opposing catabolic and anabolic pathways that share some enzymatic steps but certain reactions are unique to each pathway. Short-term regulation of gluconeogenesis is exerted at two sites—the reactions involving pyruvate and PEP and those that interconvert F1,6BP and F6P (Figure ...
... gluconeogenesis are opposing catabolic and anabolic pathways that share some enzymatic steps but certain reactions are unique to each pathway. Short-term regulation of gluconeogenesis is exerted at two sites—the reactions involving pyruvate and PEP and those that interconvert F1,6BP and F6P (Figure ...
BIOTRANSFORMATION OF DRUGS
... Oxygenation involves insertion of an O atom (from O2) into a C-H bond, forming a hydroxylated metabolite, or into a C=C double bond, forming an epoxide. A hydroxylated metabolite may be stable, or unstable. From an unstable hydroxylated metabolite a group may break off spontaneously: an alkyl group, ...
... Oxygenation involves insertion of an O atom (from O2) into a C-H bond, forming a hydroxylated metabolite, or into a C=C double bond, forming an epoxide. A hydroxylated metabolite may be stable, or unstable. From an unstable hydroxylated metabolite a group may break off spontaneously: an alkyl group, ...
The Vitamin K-dependent Carboxylase*
... residues (e. g. R –4 N or R –1 S) in the factor IX propeptide (62, 74). In these patients, the mutated factor IX is secreted into the bloodstream with an attached propeptide (62, 74). The Gla domain cannot adopt its native conformation, and, as a result, the pro-factor IX is unable to bind tightly t ...
... residues (e. g. R –4 N or R –1 S) in the factor IX propeptide (62, 74). In these patients, the mutated factor IX is secreted into the bloodstream with an attached propeptide (62, 74). The Gla domain cannot adopt its native conformation, and, as a result, the pro-factor IX is unable to bind tightly t ...
2.2. Garrido-Franco, M. Structure E. coli
... The PNP synthase octamer is organized as a tetramer of dimers AE, BF, CG and DH. The (β/α)8 domains of the corresponding monomers interact extensively about an intervening crystallographic two-fold axis, such that their barrel axes are approximately perpendicular to each other (Figure 2c). The dimer ...
... The PNP synthase octamer is organized as a tetramer of dimers AE, BF, CG and DH. The (β/α)8 domains of the corresponding monomers interact extensively about an intervening crystallographic two-fold axis, such that their barrel axes are approximately perpendicular to each other (Figure 2c). The dimer ...
Title Biotin Biosynthesis in Microorganisms (Commemoration Issue
... Since early studies of biotin biosynthesis, it has been recognized that DTB is converted to biotin during growth of various microorganisms.62-67> Using resting cells, biotin biosynthesis from DTB was demonstrated with some bacteria64,ss-79) and yeasts.71-74) There have been no studies on enzymic syn ...
... Since early studies of biotin biosynthesis, it has been recognized that DTB is converted to biotin during growth of various microorganisms.62-67> Using resting cells, biotin biosynthesis from DTB was demonstrated with some bacteria64,ss-79) and yeasts.71-74) There have been no studies on enzymic syn ...
Full Text
... of 21 PL families have a known three-dimensional structure of at least one representative (Table I). Only two families, PL12 and PL17 have as yet unassigned folds. Of these, heparan sulfate (HS) lyase family PL12 is the largest without a representative structure. Polysaccharide substrates bind to th ...
... of 21 PL families have a known three-dimensional structure of at least one representative (Table I). Only two families, PL12 and PL17 have as yet unassigned folds. Of these, heparan sulfate (HS) lyase family PL12 is the largest without a representative structure. Polysaccharide substrates bind to th ...
Contents - Elsevier
... Why are there two pyridine nucleotides, NAD+ and NADP+, differing only in the presence or absence of an extra phosphate group? One important answer is that they are members of two different oxidation– reduction systems, both based on nicotinamide but functionally independent. The experimentally meas ...
... Why are there two pyridine nucleotides, NAD+ and NADP+, differing only in the presence or absence of an extra phosphate group? One important answer is that they are members of two different oxidation– reduction systems, both based on nicotinamide but functionally independent. The experimentally meas ...
Biochemical studies of enzymes in insect cuticle hardening
... concentrations in several neurodegenerative diseases. A mammalian enzyme, glutamate decarboxylase like-1 (GADL1), has been shown to have the same substrate usage as insect ADC does, potentially contributing to the biosynthesis of taurine and/or β-alanine in mammalian species. Finally, the metabolic ...
... concentrations in several neurodegenerative diseases. A mammalian enzyme, glutamate decarboxylase like-1 (GADL1), has been shown to have the same substrate usage as insect ADC does, potentially contributing to the biosynthesis of taurine and/or β-alanine in mammalian species. Finally, the metabolic ...
C 2 R
... of BM3 Cys400) to the heme-iron, instead of a thiolate which is required to produce the active P450 (33). Mutation F87S, when applied to wild-type BM3 was previously shown to be an active enzyme with changed regioselectivity in lauric acid hydroxylation (19). However, carbonmonoxide difference spect ...
... of BM3 Cys400) to the heme-iron, instead of a thiolate which is required to produce the active P450 (33). Mutation F87S, when applied to wild-type BM3 was previously shown to be an active enzyme with changed regioselectivity in lauric acid hydroxylation (19). However, carbonmonoxide difference spect ...
principles of metabolic regulation: glucose and glycogen
... Chapter 14 we discussed three possible fates for glucose 6-phosphate in a hepatocyte: passage into glycolysis for the production of ATP, passage into the pentose phosphate pathway for the production of NADPH and pentose phosphates, or hydrolysis to glucose and phosphate to replenish blood glucose. I ...
... Chapter 14 we discussed three possible fates for glucose 6-phosphate in a hepatocyte: passage into glycolysis for the production of ATP, passage into the pentose phosphate pathway for the production of NADPH and pentose phosphates, or hydrolysis to glucose and phosphate to replenish blood glucose. I ...
On the role and formation of covalently bound flavin cofactors Heuts
... Another novel type of covalent flavin binding has been described for the NqrB and NqrC subunits of the Na+-translocating NADH-quinone reductase (Na+NQR) from Vibrio alginolyticus. In this case, FMN is covalently linked to a threonine residue via a phosphoester bond [22]. Consequently, it represents t ...
... Another novel type of covalent flavin binding has been described for the NqrB and NqrC subunits of the Na+-translocating NADH-quinone reductase (Na+NQR) from Vibrio alginolyticus. In this case, FMN is covalently linked to a threonine residue via a phosphoester bond [22]. Consequently, it represents t ...
Pyruvate Kinase - Wiley Online Library
... Kinetic studies of the pyruvate kinases of rat and human tissues have led t o the identification of three classes of isoenzymes with qualitative differences in regulatory properties. Class L, the major component in liver extracts and a minor component of kidney extracts, shows markedly sigmoidal kin ...
... Kinetic studies of the pyruvate kinases of rat and human tissues have led t o the identification of three classes of isoenzymes with qualitative differences in regulatory properties. Class L, the major component in liver extracts and a minor component of kidney extracts, shows markedly sigmoidal kin ...
REDESIGN OF CARNITINE ACETYLTRANSFERASE SPECIFICITY BY PROTEIN ENGINEERING UNIVERSIDAD DE BARCELONA
... A novel compound, the fatty acid synthase (FAS) inhibitor C75, has been proposed to pharmacologically regulate CPT I activity (Price, 2001). Structurally, C75 is a cell-permeable α-methylene-γ-butyrolactone designed to be less reactive and potentially safer than cerulenin, a natural product obtained ...
... A novel compound, the fatty acid synthase (FAS) inhibitor C75, has been proposed to pharmacologically regulate CPT I activity (Price, 2001). Structurally, C75 is a cell-permeable α-methylene-γ-butyrolactone designed to be less reactive and potentially safer than cerulenin, a natural product obtained ...
Random Mutagenesis of Luciola mingrelica Firefly Luciferase
... with subsequent isolation from the gel using a Qiagen kit. The fragment obtained was treated with restrictases NheI and BamHI, purified from low molecular weight restriction products by electrophoresis, isolated from the gel, and ligated into pLR3 plasmid cut at the same sites, thus preparing a mix ...
... with subsequent isolation from the gel using a Qiagen kit. The fragment obtained was treated with restrictases NheI and BamHI, purified from low molecular weight restriction products by electrophoresis, isolated from the gel, and ligated into pLR3 plasmid cut at the same sites, thus preparing a mix ...
Regulation of Phenylalanine and Tyrosine
... hyperbolic with K , values of 0.31 r n M for chorismate and 0.015 mM for prephenate, respectively. The substrate saturation curve of the complexed prephenate dehydratase I was sigmoid; a Km value of 0-18 mM was calculated for prephenate. Chorismate mutase, prephenate dehydratase and prephenate dehyd ...
... hyperbolic with K , values of 0.31 r n M for chorismate and 0.015 mM for prephenate, respectively. The substrate saturation curve of the complexed prephenate dehydratase I was sigmoid; a Km value of 0-18 mM was calculated for prephenate. Chorismate mutase, prephenate dehydratase and prephenate dehyd ...
Oxidation and Synthesis of Fatty Acids in Soluble Enzyme Systems
... step of fatty acid oxidation, the conversion of the fatty acid to the corresponding coenzyme A derivative (10-12). Coenzyme A (CoA) is a complex nucleotide whose structure (shown in Fig. 1) has recently been established by Lipmann and his group (13, 14). For present purposes it can be conceived of a ...
... step of fatty acid oxidation, the conversion of the fatty acid to the corresponding coenzyme A derivative (10-12). Coenzyme A (CoA) is a complex nucleotide whose structure (shown in Fig. 1) has recently been established by Lipmann and his group (13, 14). For present purposes it can be conceived of a ...
Molecular Cloning of Dog Mast Cell Tryptase and a Related Protease
... Mast cell tryptase differs markedly from other serine proteases in many of its biochemical features. It has two or more subunits which associate noncovalently as catalytically active tetramers and appears to be stored and released as an active enzyme rather than as a zymogen. No new tryptase activit ...
... Mast cell tryptase differs markedly from other serine proteases in many of its biochemical features. It has two or more subunits which associate noncovalently as catalytically active tetramers and appears to be stored and released as an active enzyme rather than as a zymogen. No new tryptase activit ...
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.