Nucleoside diphosphate kinase reaction

Thus the net result of the activity of either isozyme of succinyl-CoA synthetase is the conservation of energy as ATP. There is no change in free energy for the nucleoside diphosphate kinase reaction ATP and GTP are energetically equivalent. 

These reactions, nucleoside monophosphate kinase (reaction 1) and nucleoside diphosphate kinase (reaction 2), involve the formation and... 

Nucleoside diphosphate kinases exhibit activity over a wide pH range, but usually have optima at or near pH 7. They require the presence of divalent metals for activity, but have a low specificity in this respect, since Mg +, Mn +, Ca +, Co +, and to a lesser extent, Ni + and Zn +, may satisfy this requirement. Magnesium is evidently the physiological ion serving this enzyme s requirement for a divalent ion. The function of magnesium ion in the nucleoside diphosphate kinase reaction is apparent in the work of Colomb et al. (27), who have shown that for the enzyme from beef heart mitochondria, MgATP, but not free ATP, serves as the phosphate donor. Further, free ADP was shown to be preferred over MgADP as the phosphate acceptor. 

In summary, the nucleoside diphosphate kinase reaction is catalyzed by enzymes with broad substrate specificity many tissues show high activities of this enzyme, which is widely distributed in nature. 

FIGURE 23.6 The PEP carboxykinase reaction. GTP formed in this reaction can be converted to ATP by nucleoside diphosphate kinase, althongh liver cells in some species may not contain this enzyme. 

ADP as a substrate in enzyme reactions, ADENYLATE KINASE (or MYOKINASE) ATP SYNTHASE CREATINE KINASE NUCLEOSIDE DIPHOSPHATE KINASE PHOSPHOGLYCERATE KINASE PYRUVATE KINASE RIBONUCLEOTIDE REDUCTASE SULFATE ADENYLYLTRANSFERASE (ADP) [ADP]/[ATP] ratio,... 

NUCLEOSIDE DIPHOSPHATASE NUCLEOSIDE DIPHOSPHATE KINASE HALF-REACTIONS... 

Janin, J. Deville-Bonne, D. Nucleoside-diphosphate kinase structural and kinetic analysis of reaction pathway and phosphohistidine intermediate. Methods EnzymoL, 354, 118-134 (2002)... 

ATP is the primary high-energy phosphate compound produced by catabolism, in the processes of glycolysis, oxidative phosphorylation, and, in photosynthetic cells, photophosphorylation. Several enzymes then cany phosphoryl groups from ATP to the other nucleotides. Nucleoside diphosphate kinase, found in all cells, catalyzes the reaction... 

The formation of ATP (or GTP) at the expense of the energy released by the oxidative decarboxylation of a-ketoglutarate is a substrate-level phosphorylation, like the synthesis of ATP in the glycolytic reactions catalyzed by glyceraldehyde 3-phosphate dehydrogenase and pyruvate kinase (see Fig. 14-2). The GTP formed by succinyl-CoA synthetase can donate its terminal phosphoryl group to ADP to form ATP, in a reversible reaction catalyzed by nucleoside diphosphate kinase (p. 505) ... 

Nucleoside diphosphates are converted to triphosphates by the action of a ubiquitous enzyme, nucleoside diphosphate kinase, which catalyzes the reaction... 

Most kinases transfer chiral phospho groups with inversion and fail to catalyze partial exchange reactions that would indicate phosphoenzyme intermediates. However, nucleoside diphosphate kinase contains an active site histidine which is phosphorylated to form a phosphoenzyme.869 The enzyme catalyzes phosphorylation of nucleoside diphosphates other than ADP by a nucleotide triphosphate, usually ATP. 

If we add the equations for the reactions catalyzed by pyruvate carboxylase, phosphoenolpyruvate carboxykinase, and nucleoside diphosphate kinase, we obtain the overall reaction for conversion of pyruvate to phosphoenolpyruvate. 

The -amino groups of lysyl residues serve as attachment sites of a number of coenzymes in proteins (e.g. biotin in pyruvate carboxylase, pyridoxal phosphate in phosphorylase, lipoic acid in lipoate acetyl-transferase) and form covalent intermediates in several enzymic reactions (e.g. transaldolase, aldolase, etc.). Discussion of all of these naturally-occuring derivatives of lysine will not be attempted in this treatise, but the investigator using chemical modification of proteins should be aware of their possible presence and effect on the results of his experiments. It should be noted that e-N-phospholysine has been reported in nucleoside diphosphate kinase (Walinder 1968). 

The diphosphates are converted to the triphosphates by the ubiquitous enzyme nucleoside diphosphate kinase. Remarkably, the lack of base or sugar specificity applies to the phosphate acceptor and the phosphate donor. Hence, the general reaction is... 

Ribonucleotide reductase activity was assayed based on CDP reduction, using a modified method of Jong et al. (1998), with the [ CICDP reduction product determined as radioactivity incorporated into DNA in a series of two coupled reactions, catalyzed by nucleoside diphosphate kinase and DNA polymerase (Klenow fragment). A 40 pi reaction mixture contained 50 mM Hepes pH 7.2, 10 mM dithiothreitol. 

ATP is synthesized in the following reaction catalyzed by nucleoside diphosphate kinase ... 

Again, the configuration is inverted. Nucleoside diphosphate kinase catalyzes the same transfer, but to a nucleoside diphosphate rather than to AMP, and with retention of configuration rather than with inversion (70). The mechanism of action of adenylate kinase involves a single displacement at P and that of nucleoside diphosphate kinase involves a double displacement at P via an intermediate phosphoenzyme. Although alkaline phosphatase is not classified as a phosphotransferase, it catalyzes transphosphorylation via the same phosphoenzyme that is the intermediate in the phosphatase reaction. This enzyme catalyzes reaction... 

Reactions (35a) and (35b) are catalyzed by galactose-1-P uridylyltransferase and UDPglucose pyrophosphorylase, respectively reactions (36a) and (36b) are catalyzed by nucleoside diphosphate kinase and adenylate kinase, respectively and reactions (37a) and (37b) are catalyzed by nucleoside phosphotransferase and adenosine kinase, respectively. 

These calculations assume that mitochondrial oxidative phosphorylation produces 1.5 ATP per FADH2 oxidized and 2.5 ATP per NADH oxidized. GTP produced directly in this step yields ATP in the reaction catalyzed by nucleoside diphosphate kinase (p. XXX). 

GMP and AMP are converted to diphosphates (see here) in reactions catalyzed by guanylate kinase and adenylate kinase, respectively. Conversion of nucleoside diphosphates to nucleoside triphosphates is catalyzed by nucleoside diphosphate kinase (see here). The reaction is reversible, thus providing a way to make both ATP and GTP. The enzyme is highly active, but has broad specificity for its phosphoryl group donor (nucleoside triphosphate) and receptor (nucleoside diphosphate). 

Within the context of this review, the nucleoside diphosphate kinase (NDPK) family of proteins deserve mention by reason of their potential connection with G-proteins. They are ubiquitously distributed in various cell types and catalyse the reaction ... 

Unlike most organisms, C. thermocellum does not encode a pyruvate kinase, which would generate 2 ATP during the conversion of 2 PEP to pyruvate. Instead, the reaction(s) responsible for conversion of PEP to pyruvate are uncertain (Figure 10.2d). One possibility is the so-called malate shunt [55, 57], in which PEP is first carboxylated to oxaloacetate (OAA) with the concomitant synthesis of GTP, which can be used directly to make ATP via nucleoside-diphosphate kinase. Then, OAA can either be directly decarboxylated to pyruvate or reduced to malate and then oxidatively decarboxylated to pyruvate. The net result of these pathways is the synthesis of 2 ATP equiv. per glucose, the same as using pyruvate kinase, with the possibility of electron transfer from NADH to make NADPH. 

Figure 10.2 shows that ATP is formed by the phosphoglycerate kinase and pyruvate kinase glycolytic reactions and in the Krebs cycle by succinyl coenzyme A (CoA) synthetase in co-operation with nucleoside diphosphate kinase (Fig. 10.3). NB These reactions do...

The very active nucleoside diphosphate kinase activity of cells has been demonstrated many times (see reference 25). The general reaction... 

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