Malate dehydrogenase (decarboxylating) (EC 188.8.131.52) or NAD-malic enzyme (NAD-ME) is an enzyme that catalyzes the chemical reaction
- (S)-malate + NAD+ pyruvate + CO2 + NADH
Thus, the two substrates of this enzyme are (S)-malate and NAD+, whereas its three products are pyruvate, CO2, and NADH. Malate is oxidized to pyruvate and CO2, and NAD+ is reduced to NADH.
This enzyme belongs to the family of oxidoreductases, to be specific, 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 (decarboxylating). This enzyme participates in pyruvate metabolism and carbon fixation. NAD-malic enzyme is one of three decarboxylation enzymes used in the inorganic carbon concentrating mechanisms of C4 and CAM plants. The others are NADP-malic enzyme and PEP carboxykinase.
As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1DO8, 1EFK, 1EFL, 1PJ2, 1PJ3, 1PJ4, and 1QR6.
- Saz HJ, Hubbard JA (1957). "The oxidative decarboxylation of malate by Ascaris lumbricoides". J. Biol. Chem. 225 (2): 921–933. PMID 13416294.