Chemical specificity of pyruvate kinase from yeast.

ABSTRACT

Three analogs of phosphoenolpyruvic acid (Z)-phosphoenol-3-fluoropyruvate, (Z)-phosphoenol-3-bromopyruvate and (Z)-phosphoenol-alpha-ketobutyrate were found to be substrates for yeast pyruvate kinase (ATP pyruvate (Z)-O-phosphotransferase, EC 2.7.1.40)with maximal velocities much greater than those found for rabbit muscle pyruvate kinase. The analogs exhibited sigmoidal kinetics, which become hyperbolic upon addition of the allosteric effector, fructose 1,6-diphosphate. Moreover, the reaction of (Z)-phosphoenol-3-bromopyruvate with ADP to produce bromopyruvic acid and ATP irreversibly inhibited the enzyme with a half-life of 32 min.