Purification in a single step and kinetic characterization of the pyruvate kinase of Trypanosoma brucei

Mol Biochem Parasitol. 1988 Nov;31(2):141-7. doi: 10.1016/0166-6851(88)90165-x.

Abstract

The pyruvate kinase of Trypanosoma brucei can be purified to homogeneity in one step by affinity elution from a phosphocellulose column with the substrate phosphoenolpyruvate (PEP) and the allosteric activator fructose-2,6-diphosphate (FDP). The purified enzyme has a specific activity of 175 mumol min-1 (mg protein)-1 and a subunit molecular mass of 59 kDa as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Kinetic studies of the pure enzyme show that an increase in the PEP concentration decreases the apparent Km for adenosine diphosphate (ADP) and that an increase in the ADP concentration decreases the half saturation point (S0.5) for PEP. Likewise, the allosteric activator FDP decreases both the apparent Km for ADP and the S0.5 for PEP. ADP concentrations above 0.2 mM inhibit trypanosomal pyruvate kinase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Animals
  • Chromatography, High Pressure Liquid
  • Chromatography, Ion Exchange
  • Cytosol / enzymology
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Activation
  • Fructosediphosphates / pharmacology
  • Kinetics
  • Phosphoenolpyruvate / metabolism
  • Pyruvate Kinase / antagonists & inhibitors
  • Pyruvate Kinase / isolation & purification*
  • Pyruvate Kinase / metabolism
  • Trypanosoma brucei brucei / enzymology*
  • Trypanosoma brucei brucei / ultrastructure

Substances

  • Fructosediphosphates
  • Adenosine Diphosphate
  • Phosphoenolpyruvate
  • fructose 2,6-diphosphate
  • Pyruvate Kinase