In enzymology, a methylenetetrahydrofolate dehydrogenase (NAD+) (EC 1.5.1.15) is an enzyme that catalyzes a chemical reaction.
[1] Thus, the two substrates of this enzyme are 5,10-methylenetetrahydrofolate and NAD+, whereas its 3 products are 5,10-methenyltetrahydrofolate, NADH, and H+.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor.
This enzyme participates in one carbon pool by folate.
[2] As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 1EDZ and 1EE9.