In vivo Evidence for a Functional Glycolytic Compartment in Synchronous Yeast Cells

Continuous 14C 0 2 Evolution, Glycolytic Compartment, Pyruvate Metabolism, Synchronous, Yeast The different metabolic behaviour of endogenously produced [1-14C] pyruvate derived from [3,4-14C]glucose and of exogenously added [1-14C]pyruvate were studied with synchronous yeast cell populations, under conditions which differentially influenced the activities of pyruvate decarboxylase in the cytoplasm and pyruvate dehydrogenase in the mitochondria. Endogenously produced [1-14C]pyruvate is decarboxylated almost exclusively by PDC under anaerobic condi­ tions, in contrast to added [1-14C]pyruvate which is decarboxylated under aerobic conditions by the action of PDH mainly. Whereas 14C 0 2 evolution from exogenous [l-14C]pyruvate can be diluted proportionally by addition of pyruvate, this is not the case for 14C 0 2 evolution from endogenous [1-14C]pyruvate. It is suggested that glycolysis or at least some constituents of it might be arranged in such a manner that the resulting complex behaves as a functional compartment, meaning that it is almost inaccessible to exogenously added pyruvate.