Malate dehydrogenase (decarboxylating) explained

NAD-malic enzyme
Ec Number:	1.1.1.39
Cas Number:	9028-46-0
Go Code:	0004471
Width:	270

Malate dehydrogenase (decarboxylating) or NAD-malic enzyme (NAD-ME) is an enzyme that catalyzes the chemical reaction

(S)-malate + NAD⁺

\rightleftharpoons 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.^{[1] [2]}

References

• Saz HJ, Hubbard JA . 1957 . The oxidative decarboxylation of malate by Ascaris lumbricoides . J. Biol. Chem. . 225 . 921 - 933 . 13416294 . 2.

Notes and References

1. Book: Sage RF, Monson RK . Kanai R, Edwards, GE . C₄ Plant Biology . 1999 . 43–87 . 3. The Biochemistry of C₄ Photosynthesis . 0126144400.
2. Christopher JT, Holtum JA . 1996 . Patterns of carbon partitioning in leaves of Crassulacean acid metabolism species during deacidification . Plant Physiol. . 112 . 1 . 393–399 . 12226397 . 157961 . 10.1104/pp.112.1.393.