[Pyruvate decarboxylase inactivation by interaction with substrate and molecular oxygen].

Pyruvate may promote the yeast pyruvate decarboxylase inactivation when affected by molecular oxygen. In the presence of pyruvate and O2 inactivation of enzyme increases with the initial substrate concentration increasing. pH-dependence of pyruvate decarboxylase inactivation under joint action of substrate and O2 has maximum in the region 6.9-7.5. It is suggested that the influence of pyruvate and molecular oxygen is connected with the coenzyme-substrate complex oxidation in an active site of yeast pyruvate decarboxylase on the steps preceding the release of free acetaldehyde.