Pyruvate, orthophosphate dikinase

PYRUVATE, ORTHOPHOSPHATE DIKINASE PYRUVATE OXIDASE Pyruvate, phosphate dikinase,... 

Aside from PEPCase, a number of other CAM-related genes have been partially characterised (Table 1). These include cDNA clones for pyruvate, orthophosphate dikinase (PPDK), a specific NADP malate dehydrogenase (MDH), glyceraldehyde phosphate dehydrogenase (GaPDH) and NADP-dependent malic enzyme (MOD). Previous studies indicated that the enzymatic activities of these gene products increased upon salt stress in the ice plant (Holtum Winter, 1982). As in the case... 

NADP-ME version of C4 metabolism This uses the equivalent of two ATP per carbon fixation one ATP is converted to AMP and its two phosphate groups are used, one to phosphorylate pyruvate, the other to phosphorylate phosphate to pyrophosphate, which, rather redundantly is immediately cleaved to two single phosphates. The enzyme performing this double phosphorylation is pyruvate/ orthophosphate dikinase. This is simplified in the diagram above. 

Sakakibara T, S.Murakami, Eisaki N, Nakajima M, Imai K. An enzymatic cycling method using pyruvate orthophosphate dikinase and firefly luciferase for the simultaneous determination of ATP and AMP(RNA). Anal Biochem 1999 268 94-101. 

Fig. 6.3. Carbon dioxide-fixing pathway in the C4-plants (prepared mainly on the basis of Hatch et al., 1967). Circled numbers 1, phosphoenolpyruvate carboxylase 2, malate dehydrogenase (NADP ) 3, malate dehydrogenase (NADP ) (OAA decarboxylating) (= malic enzyme) 4, Rubisco 5, pyruvate orthophosphate dikinase. Pi, phosphate PPi, diphosphate...

Harnesyl diphosphate nthase 66 Pyruvate orthophosphate dikinase 103... 

MOONS, A., VALCKE, R., VAN MONTAGU, M., Low-oxygen stress and water deficit induce cytosolic pyruvate orthophosphate dikinase (PPDK) expression in roots of rice, a C3 plant, Plant J., 1998, 15, 89-98. 

Regulation of Pyruvate,Orthophosphate Dikinase From Maize Leaves.Magnesium-dependent Dimer-tetramer Interconversion. 

Pyruvate, orthophosphate dikinase(PPDK, EC 2.7.9.1.), a key enzyme in the C4 pathway of photosynthesis, catalyzes the formation of phosphoenolpyruvate(PEP) as follows ... 

Regulation of Pyruvate-Orthophosphate Dikinase from Maize Leaves. Magnesium-Dependent Dimer-Tetramer Interconversion 183... 

Conversion of acetyl-CoA to triose phosphate (glyceraldehyde 3-phosphate and dihydroxyacetone phosphate) requires that two of the reactions of the catabolic pathway be replaced by alternative reactions catalysed by different enzymes these are (i) the pyruvate dehydrogenase complex-catalysed oxidative decarboxylation of pyruvate to acetyl-CoA, which is replac by the pyruvate synthase (EC 1.2.7.1)-catalysed reductive carboxylation of acetyl-CoA (eq. 3 I, Fig.), in which the reductant is reduced ferredoxin (Fd,ed). and (ii) the pyruvate kinase (EC 2.7.1.40)-catalysed, ATP-generating conversion of phosphoeno/pyruvate to pyruvate, which is replaced by the pyruvate, orthophosphate dikinase (EC 2.7.9.1)-catalysed, ATP-dtiven conversion of pyruvate to phosphoeno/pyruvate (eq. 4 F, Fig.),... 

Sugiyama,T., Laetsch,W.M. Occurence of pyruvate orthophosphate dikinase in the succulent plant, Kalanchoe daigremontiana Hamet et Perr. Plant Physiol. 56, 605-607 (1975) Sutton, B.C. Regulation of carbohydrate metabolism in succulent plants. Ph.D. Thesis, Aust. Nat. Univ. (1974 a)... 

---