Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A radiometric method has been devised for the determination of small quantities of NADH formed in preceding dehydrogenase reactions. In a coupled enzymatic reaction, phosphoglycerate kinase (PGK) catalyzes the transfer of [32P]orthophosphate from [gamma-32P]ATP to 3-phosphoglycerate; the intermediate, 1,3-[1-32P]diphosphoglycerate, is dephosphorylated by glyceraldehyde-3-phosphate dehydrogenase (GAP-DH). [32P]Orthophosphate is released proportionally to NADH and can be measured after adsorption of [gamma-32P]ATP to activated charcoal. With this method, 0.2 pmol of NADH are detectable in the presence of a 10(4)-fold excess of NAD over NADH.
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PMID:A radiometric method for the determination of NADH in subpicomole amounts. 337 44

In the process of defining the recruitment of fuel and pathway selection in rainbow trout fast-twitch white skeletal muscle, it was clear that the near-maximal myosin adenosinetriphosphatase activity during a 10-s sprint was supported solely by phosphocreatine hydrolysis. A conservative estimate of the ATP turnover was 188 mumol X g wet wt-1 X min-1. It was not until the rate and force of contraction decreased that the relative contribution of anaerobic glycogenolysis became increasingly important. Over a 10-min period of burst swimming at approximately 120% of maximum aerobic steady-state swimming velocity of trout determined in a Brett-type swim tunnel, fatigue was associated with the near-depletion of glycogen in white muscle. The ATP turnover supported by anaerobic glycogenolysis was 78 mumol X g wet wt-1 X min-1. The glycolytic pathway appeared functional at this time with control sites being identified at hexokinase and phosphofructokinase (PFK-1). PFK-1 did not appear to be inhibited by low muscle pH (pH 6.66). In another exercise protocol lasting 30 min, complete exhaustion was related to glycogen depletion. The sum of all glycolytic intermediates from glucose 6-phosphate to pyruvate at exhaustion decreased by a dramatic 80% compared with the 25% decrease for the 10-min fatigue swimming protocol. This large depletion of glycolytic intermediates was accompanied by an 80% fall in ATP, a 70-80% reduction in the ATP/ADP and phosphorylation potential, and a 2.5-fold increase in the NAD/NADH. Associated with these changes was a marked displacement of the phosphoglycerate kinase (PGK), and the combined glyceraldehyde-3-phosphate dehydrogenase-PGK reactions from thermodynamic equilibrium. As a general conclusion, fatigue and exhaustion should be viewed as a multicomponent biochemical process in response to low glycogen and not leveled at one particular step of the glycolytic pathway.
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PMID:Regulation of anaerobic ATP-generating pathways in trout fast-twitch skeletal muscle. 360 83

Glycosomes, the microbodies of Trypanosoma brucei, contain a number of enzymes involved in glucose and glycerol metabolism. The biogenesis of three of these enzymes has been studied. Aldolase, D-glyceraldehyde-3-phosphate dehydrogenase and NAD-linked glycerol-3-phosphate dehydrogenase are all synthesized in the cytosol on free rather than on membrane-bound polysomes. In vitro, as well as in vivo, these polypeptides are synthesized at their mature size, and no evidence was found for any processing upon entry into the glycosomes. Continuous and pulse-chase labelling experiments with procyclic trypomastigotes revealed that the enzymes have a half-life in the cytosol of approximately 3 min or less, and then turn over rapidly in the glycosomes, with half-lives as short as 30 min.
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PMID:Biogenesis of the glycosome in Trypanosoma brucei: the synthesis, translocation and turnover of glycosomal polypeptides. 360 83

Crude extracts from cells of Pseudomonas syringae pv. phaseolicola, a fluorescent pseudomonad, when grown on glucose contain a NAD-linked 6-phosphogluconate dehydrogenase. The reaction of the enzyme, which produces 14CO2 from 1-14C-6-phosphogluconate, is not inhibited by NaF, a potent inhibitor of the Enter-Doudoroff (ED) pathway enzyme 6-phosphogluconate dehydratase. In the presence of phosphate or arsenate ions the NAD-linked glyceraldehyde-3-phosphate dehydrogenase reacts with glyceraldehyde-3-phosphate which, in the ED pathway, is produced from 6-phosphogluconate and overlaps the 6-phosphogluconate dehydrogenase reaction. Only a small proportion of glucose is metabolized via the 6-phosphogluconate dehydrogenase/oxidative pentose phosphate pathway.
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PMID:[Demonstration of an NAD-dependent 6-phosphogluconate dehydrogenase in Pseudomonas syringae pv. phaseolicola]. 362 76

We have identified the site labeled by arylazido-beta-alanyl-NAD+ (A3'-O-(3-[N-(4-azido-2-nitrophenyl)amino]propionyl)NAD+) in rabbit muscle glyceraldehyde-3-phosphate dehydrogenase by microsequencing and fast atom bombardment mass spectrometry. This NAD+ photoaffinity analogue has been previously demonstrated to modify glyceraldehyde-3-phosphate dehydrogenase in a very specific manner and probably at the active site of the enzyme [Chen, S., Davis, H., Vierra, J. R., & Guillory, R. J. (1984) Biochem. Biophys. Stud. Proteins Nucleic Acids, Proc. Int. Symp., 3rd, 407-425]. The label is associated exclusively with a tryptic peptide that has the sequence Ile-Val-Ser-Asn-Ala-Ser-Cys-Thr-Thr-Asn. In comparison to the amino acid sequence of glyceraldehyde-3-phosphate dehydrogenase from other species, this peptide is in a highly conserved region and is part of the active site of the enzyme. The cysteine residue at position seven was predominantly labeled and suggested to be the site modified by arylazido-beta-alanyl-NAD+. This cysteine residue corresponds to the Cys-149 in the pig muscle enzyme, which has been shown to be an essential residue for the enzyme activity. The present investigation clearly demonstrates that arylazido-beta-alanyl-NAD+ is a useful photoaffinity probe to characterize the active sites of NAD(H)-dependent enzymes.
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PMID:Identification of the arylazido-beta-alanyl-NAD+-modified site in rabbit muscle glyceraldehyde-3-phosphate dehydrogenase by microsequencing and fast atom bombardment mass spectrometry. 377 66

Changes in intrinsic protein fluorescence of lobster muscle D-glyceraldehyde-3-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate: NAD+ oxidoreductase (phosphorylating), EC 1.2.1.12) have been compared with inactivation of the enzyme during denaturation in guanidine solutions. The holoenzyme is completely inactivated at guanidine concentrations less than 0.5 M and this is accompanied by a red shift of the emission maximum at 335 nm and a marked decrease in intensity of the intrinsic fluorescence. At 0.5 M guanidine, the inactivation is a slow process, with a first-order rate constant of 2.4 X 10(-3) s-1. A further red shift in the emission maximum and a decrease in intensity occur at guanidine concentrations higher than 1.5 M. The emission peak at 410 nm of the fluorescent NAD derivative introduced at the active site of this enzyme (Tsou, C.L. et al. (1983) Biochem. Soc. Trans. 11, 425-429) shows both a red shift and a marked decrease in intensity at the same guanidine concentration required to bring about the inactivation and the initial changes in the intrinsic fluorescence of the holoenzyme. It appears that treatment by low guanidine concentrations leads to both complete inactivation and perturbation of the active site conformation and that a tryptophan residue is situated at or near the active site.
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PMID:Conformational and activity changes during guanidine denaturation of D-glyceraldehyde-3-phosphate dehydrogenase. 379 May 96

Trypanosoma brucei contains two glyceraldehyde-phosphate (GAPDH; EC 1.2.1.12) isoenzymes; one is located in glycosomes and represents 80% of the total activity, whereas the other is present in the cytosol. The purification of the cytosolic GAPDH, which is identical in both bloodstream-form and insect-stage trypanosomes, is described, and the enzyme compared with its glycosomal counterpart. Cytosolic GAPDH is specific for NAD. It is a tetrameric enzyme with subunits of 33.5 kDa, 5 kDa smaller than those of the glycosomal GAPDH. The native enzyme has a pI of 7.9, which is 1.5 pH units less basic than the glycosomal enzyme. Both enzymes display maximal activity at pH 8 but the cytosolic enzyme has a much broader activity profile especially towards lower pH values. Sequence comparison of the first 85 amino acids reveals that the N-terminal parts of both isoenzymes differ by 52%. The N terminus of the cytosolic isoenzyme resembles the corresponding N termini of ten other known GAPDH sequences in that they all lack three amino-acid insertions, which so far only have been found in the glycosomal isoenzyme of T. brucei. This observation explains in part the great difference in subunit size between the two T. brucei isoenzymes and suggests that at least one of these insertions is responsible for import of the glycosomal isoenzyme into the organelle.
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PMID:Glyceraldehyde-phosphate dehydrogenase from Trypanosoma brucei. Comparison of the glycosomal and cytosolic isoenzymes. 383 Jan 53

The redox status of three biological components capable of undergoing oxidation-reduction reactions, glutathione, NAD and NADP, were determined in muscle tissues of young and old rats. A considerable increase in the relative concentration of the oxidized form, at the expense of the reduced one was found in the old tissue reflecting a significantly less reducing environment than in young cells. The effects of varying the ratio of reduced/oxidized glutathione in vitro on the activity of the enzyme glyceraldehyde-3-phosphate dehydrogenase extracted from young and old animals were compared. It was found that concentrations of GSSG as found in old muscle tissue do not affect enzyme samples extracted from young muscle. The accumulation of oxidized glutathione observed in old cells does not, therefore, directly cause the age-related activity loss of this enzyme.
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PMID:Age-related changes in the redox status of rat muscle cells and their role in enzyme-aging. 398 83

A semiautomatic determination of glycerol is described, in which luminescence produced by bacterial NADH-linked luciferase is measured by an automatic luminescence analyser (Berthold LB 950 T). The glycerol determination is based on the enzymatic conversion of glycerol to 3-phosphoglycerate, made irreversible by the presence of arsenate. NADH, formed in the glycerol-3-phosphate and glyceraldehyde-3-phosphate dehydrogenase reactions, is subsequently determined by the bacterial luciferase system. Stable kinetics of light emission were obtained by reducing the catalytic concentration of NAD(P)H: FMN oxidoreductase from 85 U/1 to 8.5 U/1. This method was applied to serum samples and validated by comparison with an enzymatic fluorimetric method. The new method is approximately 10 times more sensitive than the fluorimetric one. Moreover, it is simpler, more convenient, less time consuming and also less expensive than spectrophotometric, fluorimetric or radiochemical methods used for glycerol determination.
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PMID:Semiautomatic bioluminescence determination of glycerol using a computer controlled luminescence analyser (Berthold LB 950 T). 398 81

The rate coefficient for (22)Na release from previously labeled human erythrocytes was determined in the presence of 0.1-10 mM sodium fluoride (F). The oxidized nicotinamide adenine dinucleotide (NAD(+)) level at the end of 2 hr of incubation in tris(hydroxymethyl)aminomethane (Tris)-Ringer medium was also measured. Both parameters decreased proportionately as F concentration was raised. Both F-induced changes were immediate and were reversed by 10 mM pyruvate. The decrease in NAD(+) concentration following enolase inhibition by F is attributed to a diminished rate of formation in the reaction catalyzed by lactic dehydrogenase (LDH) with undiminished continued utilization in the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase (GAPDH). It is postulated that the NAD(+) lowering limited the GAPDH step, resulting in proportionate decreases in the rates of phosphoglycerate kinase (PGK) and Na,K-dependent adenosine triphosphatase (Na,K-ATPase), a reaction sequence thought to link glycolysis with active Na extrusion. Adding pyruvate with F increased NAD(+) production at the LDH step, thus reactivating GAPDH, PGK, and Na,K-ATPase and leading to the observed restoration of (22)Na release. The results suggest, therefore, that F inhibits active Na transport in intact human erythrocytes indirectly through a lowering of NAD(+), although, direct inhibition of the Na,K-ATPase by F may possibly occur simultaneously.
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PMID:The role of oxidized nicotinamide adenine dinucleotide in fluoride inhibition of active sodium transport in human erythrocytes. 434 51


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