Purification and characterization of hydroxypyruvate reductase from the facultative methylotroph Methylobacterium extorquens AM1

J Bacteriol. 1991 Nov;173(22):7228-32. doi: 10.1128/jb.173.22.7228-7232.1991.


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.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alcohol Oxidoreductases / isolation & purification*
  • Alcohol Oxidoreductases / metabolism*
  • Chromatography
  • Chromatography, Affinity
  • Chromatography, Gel
  • Chromatography, Ion Exchange
  • Durapatite
  • Electrophoresis, Polyacrylamide Gel
  • Gram-Negative Aerobic Bacteria / enzymology*
  • Hydroxyapatites
  • Hydroxypyruvate Reductase
  • Kinetics
  • Macromolecular Substances
  • Molecular Weight
  • Substrate Specificity


  • Hydroxyapatites
  • Macromolecular Substances
  • Durapatite
  • Alcohol Oxidoreductases
  • Hydroxypyruvate Reductase