Dogfish M4 lactate dehydrogenase: reversible inactivation by pyridoxal 5′-phosphate and complete protection in complexes that mimic the active ternary complex

Abstract

Dogfish M4 lactate dehydrogenase, like the corresponding pig enzyme, is inactivated by pyridoxal 5′-phosphate through modification of a single essential lysine residue. The activity is completely protected in the complexes E-NAD+-oxalate, E-NADH-oxamate and E-(NAD+-pyruvate adduct), but only partially protected in E-NAD+, E-NADH, E-NAD+-oxamate and E-NADH-oxalate.