RESUMO
A complete list of all steady-state kinetic constants for the yeast alcohol dehydrogenase (EC 1.1.1.1) catalyzed oxidation of ethanol, propan-1-ol and butan-1-ol, and for the reduction of acetaldehyde and propionaldehyde was collected in the pH range 6-10, and an appropriate pH profile for each constant was constructed. A common minimal mechanism with all these substrates has been postulated and pKa values and the pH independent limiting values have been assigned for the rate constants.
Assuntos
Álcool Desidrogenase/química , Álcoois/química , Aldeídos/química , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Saccharomyces cerevisiae/enzimologia , Especificidade por SubstratoRESUMO
The kinetic mechanism of yeast alcohol dehydrogenase (EC 1.1.1.1) activity with the redox pair 2-propanol/acetone has been probed in detail by the application of initial rate studies in the absence and in the presence of products, and a dead-end inhibitor pyrazole. An overall steady-state random Bi Bi mechanism in both directions, with the formation of both abortive ternary complexes, enzyme.NADH.2-propanol and enzyme.NAD+.acetone has been observed. A complete list of steady-state kinetic constants are also reported for the redox pair (S)-(+)-2-butanol/2-butanone.