Irreversible inactivation of yeast glucose-6-P dehydrogenase by penicillin G.

Yeast glucose-6-P dehydrogenase is irreversibly inactivated by penicillin G. Kinetic data show that 1 molecule of penicillin G reacts with each active unit when the enzyme is inactivated. The rate of inactivation increases greatly with increasing pH. This irreversible inactivation by penicillin G is largely prevented by pyridoxal-P, a reversible inactivator or this enzyme. Prior treatment of penicillin G with penicillinase totally abolishes its ability to inactivate the enzyme.