In addition to the NAD-dependent oxidative decarboxylation of L-malate, the enzyme catalyzes the decarboxylation of oxaloacetate. (S)-malate + NAD(+) = CO2 + NADH + pyruvate H(+) + oxaloacetate = CO2 + pyruvate Divalent metal cations. Prefers magnesium or manganese. The activity is enhanced 5-7 times by ammonium and potassium. Homotetramer. This enzyme has a higher affinity for NAD than for NADP. Belongs to the malic enzymes family.