Pyruvate — Oxaloacetate exchange reaction in baker's yeast

Abstract

The results in this paper show that extracts of baker's yeast contain a pyruvate carboxylase which catalyzes the carboxylation of pyruvate to form oxaloacetate and the exchange of oxaloacetate and pyruvate. The carboxylation reaction requires GSH, MgCl₂, ATP and is stimulated by acetyl-CoA. In the exchange reaction the transfer of the β-COOH group of oxaloacetate to pyruvate does not require ATP and is not stimulated by acetyl-CoA. Both reactions are inhibited by low concentrations of avidin and p-chloromercuribenzoate.