NAD(P)+-independent aldehyde dehydrogenase from Pseudomonas testosteroni. A novel type of molybdenum-containing hydroxylase.
Aldehyde dehydrogenase from Pseudomonas testosteroni was purified to homogeneity. The enzyme has a pH optimum of 8.2, uses a wide range of aldehydes as substrates and cationic dyes (Wurster's blue, phenazine methosulphate and thionine), but not anionic dyes (ferricyanide and 2.6-dichloroindophenol), NAD(P)+ or O2, as electron acceptors. Haem c and pyrroloquinoline quinone appeared to be absent but the common cofactors of molybdenum hydroxylases were present. Xanthine was not a substrate and allopurinol was not an inhibitor. Alcohols were inhibitors only when turnover of the enzyme occurred in aldehyde conversion. The enzyme has a relative molecular mass of 186,000, consists of two subunits of equal size (Mr 92,000), and 1 enzyme molecule contains 1 FAD, 1 molybdopterin cofactor, 4 Fe and 4 S. It is a novel type of NAD(P)+-independent aldehyde dehydrogenase since its catalytic and physicochemical properties are quite different from those reported for already known aldehyde-converting enzymes like haemoprotein aldehyde dehydrogenase (EC 1.2.99.3), quino-protein alcohol dehydrogenases (EC 1.1.99.8) and molybdenum hydroxylases.
D000444:Aldehyde Dehydrogenase / Q000302:isolation & purification* / Q000378:metabolism; D002384:Catalysis; D003067:Coenzymes / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D007501:Iron / Q000032:analysis; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000302:isolation & purification*; D008970:Molecular Weight; D008982:Molybdenum / Q000032:analysis*; D009249:NADP / Q000502:physiology; D011549:Pseudomonas / Q000201:enzymology*; D013379:Substrate Specificity
D003067:Coenzymes; D009249:NADP; D008982:Molybdenum; D007501:Iron; D006899:Mixed Function Oxygenases; D000444:Aldehyde Dehydrogenase