Aldehyde Dehydrogenases: What can be Learned from a Baker’s Dozen Sequences?

Abstract

Aldehyde dehydrogenases (E. C. 1.2.1.3, ALDH) exist in multiple molecular forms which differ in their physical and/or their functional properties (Weiner, 1979). Aldehyde dehydrogenase has been identified in virtually every organism and tissue examined. Distinct ALDHs have been identified in the mitochondrial, microsomal and cytosolic compartments of the cell (Tottmar et al., 1973; Greenfield and Pietruszko, 1977; Lindahl and Evces, 1984). Some forms are constitutive, some inducible (Deitrich, 1971; Deitrich et al., 1977). Tetrameric and dimeric functional forms are known. Some forms display broad substrate specificity, oxidizing a variety of aliphatic and aromatic aldehydes. Other forms possess much narrower substrate preferences, utilizing small aliphatic aldehydes. Kinetic studies have indicated that acetaldehyde derived from ethanol oxidation, medium chain length aliphatic aldehydes derived from membrane lipid peroxidation and perhaps some aldehydes generated from neurotransmitter metabolism are potential physiological substrates for one or more ALDH forms (Tank et al., 1981; Esterbauer, 1982; Weiner, 1982; Mitchell and Petersen, 1989). While all aldehyde dehydrogenases likely use NAD+ as coenzyme in vivo, some forms can utilize NADP+ in vitro.