Purification and characterization of hydroxypyruvate reductase from the facultative methylotroph Methylobacterium extorquens AM1.
Hydroxypyruvate reductase was purified to homogeneity from the facultative methylotroph Methylobacterium extorquens AM1. It has a molecular mass of about 71 kDa, and it consists of two identical subunits with a molecular mass of about 37 kDa. This enzyme uses both NADH (Km = 0.04 mM) and NADPH (Km = 0.06 mM) as cofactors, uses hydroxypyruvate (Km = 0.1 mM) and glyoxylate (Km = 1.5 mM) as the only substrates for the forward reaction, and carries out the reverse reaction with glycerate (Km = 2.6 mM) only. It was not possible to detect the conversion of glycolate to glyoxylate, a proposed role for this enzyme. Kinetics and inhibitory studies of the enzyme from M. extorquens AM1 suggest that hydroxypyruvate reductase is not a site for regulation of the serine cycle at the level of enzyme activity.
Chistoserdova
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W.M. Keck Laboratories, California Institute of Technology, Pasadena 91125.
Lidstrom
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D000429:Alcohol Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism*; D002845:Chromatography; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology*; D006882:Hydroxyapatites; D050537:Hydroxypyruvate Reductase; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D013379:Substrate Specificity
D006882:Hydroxyapatites; D046911:Macromolecular Substances; D017886:Durapatite; D000429:Alcohol Oxidoreductases; D050537:Hydroxypyruvate Reductase