Catalyzes the reduction of aromatic alpha-keto acids in the presence of NADH. Plays essential roles in the malate-aspartate shuttle and the tricarboxylic acid cycle, important in mitochondrial NADH supply for oxidative phosphorylation. (S)-malate + NAD(+) = H(+) + NADH + oxaloacetate Homodimer. ISGylated. Acetylation at Lys-118 dramatically enhances enzymatic activity and promotes adipogenic differentiation. Belongs to the LDH/MDH superfamily. MDH type 2 family.