In enzymology, a malate dehydrogenase (oxaloacetate-decarboxylating) (EC 1.1.1.38) is an enzyme that catalyzes the chemical reaction below

(S)-malate + NAD⁺ ${\displaystyle \rightleftharpoons }$ pyruvate + CO₂ + NADH

Thus, the two substrates of this enzyme are (S)-malate and NAD⁺, whereas its 3 products are pyruvate, CO₂, and NADH.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is (S)-malate:NAD⁺ oxidoreductase (oxaloacetate-decarboxylating). Other names in common use include malic enzyme, pyruvic-malic carboxylase, NAD⁺-specific malic enzyme, NAD⁺-malic enzyme, and NAD⁺-linked malic enzyme. This enzyme participates in pyruvate metabolism.

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 1DO8, 1EFK, 1EFL, 1GZ3, 1LLQ, 1O0S, 1PJ2, 1PJ3, 1PJ4, 1PJL, 1QR6, 1WW8, and 2DVM.

• ME2 (gene)