In enzymology, an aldehyde dehydrogenase [NAD(P)+] (EC 1.2.1.5) is an enzyme that catalyzes the chemical reaction

an aldehyde + NAD(P)+ + H₂O an acid + NAD(P)H + H⁺

The 4 substrates of this enzyme are aldehyde, NAD⁺, NADP⁺, and H₂O, whereas its 4 products are acid, NADH, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is aldehyde:NAD(P)+ oxidoreductase. Other names in common use include aldehyde dehydrogenase [NAD(P)+], and ALDH. This enzyme participates in 5 metabolic pathways: glycolysis / gluconeogenesis, histidine metabolism, tyrosine metabolism, phenylalanine metabolism, and metabolism of xenobiotics by cytochrome p450.

As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes 1AD3, 1EYY, 1EZ0, and 2AMF.

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