Glycerate kinase and

Glycolysis A net formation of two results from the formation of lactate from one molecule of glucose, generated in two reactions catalyzed by phospho-glycerate kinase and pyruvate kinase, respectively (Figure 17-2). 

Like all anhydrides (Section 21.5), the mixed carboxylic-phosphoric anhydride is a reactive substrate in nucleophilic acyl (or phosphoryl) substitution reactions. Reaction of 1,3-bisphosphoglycerate with, ADP occurs in step 7 by substitution on phosphorus, resulting in transfer of a phosphate group to, ADP and giving ATP plus 3-phosphoglycerate. T he process is catalyzed by phospho-glycerate kinase and requires Mg " " as cofactor. Together, steps 6 and 7 accomplish the oxidation of an aldehyde to a carboxylic acid. 

Reduction of phosphoglycerate by the combined action of phospho-glycerate kinase and triose phosphate ddiydrogenase results in the formation of triose phosphate (XII). This reduction is presumably effected... 

Competitive inhibitors are inhibitors which have an effect on the but not on the V of an enzyme-catalysed reaction. The V is unchanged because the number of functional active sites is not altered but a greater substrate concentration is required to achieve the maximum utilization of the sites. Consequently, the for the substrate increases. Competitive inhibition may be overcome by the addition of more substrate to the enzyme reaction mixture. Competitive inhibitors often bear a structural similarity to the substrate and compete with the substrate for the active sites of the enzyme, i.e. they are isosteric. However, competitive inhibitors are not necessarily structurally analogous to the substrate, e.g. salicylate inhibition of 3-phospho-glycerate kinase, and may bind to a site distinct from the active site, e.g. L-isoleucine inhibition of threonine deaminase from Escherichia coli. The classical example of competitive inhibition is the action of malonate on succinate dehydrogenase (Figure 6.9) which advanced the elucidation of the... 

Usuda H, GE Edwards (1980) Localization of glycerate kinase and some enzymes for sucrose synthesis in C3 and C4 plants. Plant PhysioL 65, 1017-1022. 

Samson, L, Kerremans, L., Rozenski, J., Samyn, B., Van beeumen, J., and Herdewijn, P. Identification of a peptide inhibitor against glycosomal phospho-glycerate kinase of Trypanosoma bmcei by a synthetic peptide library... 

Harlos K, Vas M, Blake CF. Crystal structure of the binary complex of pig muscle phosphogycerate kinase and its substrate 3-phospho-D-glycerate. Proteins Struct Funct Genet 1992 12 133-144. 

Huskins, K.R. Bernhard, S.A. Dahlquist, F.W. Halibut muscle 3-phospho-glycerate kinase. Chemical and physical properties of the enzyme and its substrate complexes. Biochemistry, 21, 4180-4188 (1982)... 

In Tp. acidophilum we have also found the production of pyruvate and glyceraldehyde via a non-phosphorylated Entner-Doudoroff pathway [2,14]. Furthermore, we have demonstrated that the glyceraldehyde is oxidised to glycerate, which is then converted to 2-phosphoglycerate by glycerate kinase. Enolase and pyruvate kinase complete the production of a second molecule of pyruvate (Fig. 3). Again, we have characterised the pathway enzymically and by the identification of intermediates [14], and evidence for its in vivo operation has been gained from radiorespirometric studies [2]. 

Fig. 14. Proposed pathway of maltose and of pyruvate fermentation to acetate, H2 and CO2 in Pyrococcus furiosus. Fdox, oxidized ferredoxin Fdred, reduced ferredoxin CoA, coenzymeA. Numbers in circles refer to enzymes involved (1) Q-glucosidase [296] (2) glucoserferredoxin oxidoreductase (3) gluconate dehydratase (this enzyme has not been detected so far in Pyrococcus furiosus) (4) 2-keto-3-deoxygluconate aldolase (5) glyceraldehyde ferredoxin oxidoreductase (6) glycerate kinase (2-phosphoglycerate forming) (7) enolase (8) pyruvate kinase (9) pyruvateiferredoxin oxidoreductase (10) ADP-forming acetyl-CoA synthetase (11)...

Fig. 1. Main routes involved in the synthesis and interconversion of glycine and serine in plants. The various steps are numbered, and the necessary enzymes are as follows 1, glycolate oxidase, E.C. 1.1.3.1 2, aminotransferases, serine, E.C. 2.6.1.45, and glutamate, E.C. 2.6.1.4, glyoxylate aminotransferases 3, enzyme complex in mitochondria (see Fig. 2) 4, serine-glyoxylate aminotransferase, E.C. 2.6.1.45 5, glycerate dehydrogenase, E.C. 1.1.1.29 6, glycerate kinase E.C. 2.7.1.31 7, D-3-phosphoglycerate phosphatase, E.C. 3.1.3.38 8, d-3-phosphoglycerate dehydrogenase, E.C. 1.1.1.95 9, phosphoserine aminotransferase, E.C. 2.6.1.52 10, phosphoserine phosphatase, E.C. 3.1.3.3 11, serine hydroxymethyltransferase E.C. 2.1.2.1 12, nonenzymatic decarboxylation 13, formyl tetrahydrofolate synthetase, E.C. 6.3.4.3 14, isocitrate iyase, E.C. 4.1.3.1.

DAS have been determined for a number of proteins, with an emphasis on proteins which contain two tryptophan residues. In these cases one hopes that each tryptophan will display a single decay time, so that the I S represent the emission spectra of the individual residues. One example is provided by a study of yeast 3-phospho-glycerate kinase (3-FGK), which has two tryptophan residues. Rom a number of pH- and wavelengdi-dependent measurements, the 0.6-ns component in die decay was associated with one residue, and the 3.1- and 7.0-ns components were associated widi die second tryptophan residue. The wavelength-dependent intensity decays were... 

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