title: A study of the oxidation of butan-1-ol and propan-2-ol by nicotinamide-adenine dinucleotide catalysed by yeast alcohol dehydrogenase.
abstract: 1. The kinetics of oxidation of butan-1-ol and propan-2-ol by NAD+, catalysed by yeast alcohol dehydrogenase, were studied at 25 degrees C from pH 5.5 to 10, and at pH 7.05 from 14 degrees to 44 degrees C, 2. Under all conditions studied the results are consistent with a mechanism whereby some dissociation of coenzyme from the active enzyme-NAD+-alcohol ternary complexes occurs, and the mechanism is therefore not strictly compulsory order. 3. A primary 2H isotopic effect on the maximum rates of oxidation of [1-2H2]butan-1-ol and [2H7]propan-2-ol was found at 25 degrees C over the pH range 5.5-10. Further, in stopped-flow experiments at pH 7.05 and 25 degrees C, there was no transient formation of NADH in the oxidation of butan-1-ol and propan-2-ol. The principal rate-limiting step in the oxidation of dependence on pH of the maximum rates of oxidation of butan-1-ol and propan-2-ol is consisten with the possibility that histidine and cysteine residues may affect or control catalysis.
mesh_terms: D000433:1-Propanol / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000378:metabolism*; D000440:Butanols / Q000378:metabolism*; D002384:Catalysis; D003545:Cysteine; D004492:Edetic Acid; D004789:Enzyme Activation; D006639:Histidine; D007700:Kinetics; D008433:Mathematics; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D013696:Temperature; D015003:Yeasts / Q000201:enzymology
chemical_list: D000440:Butanols; D009243:NAD; D006639:Histidine; D000433:1-Propanol; D004492:Edetic Acid; D000429:Alcohol Oxidoreductases; D003545:Cysteine