DEHYDROGENASE ACTIVITY FOR HIGHER ALCOHOLS IN CELL-FREE EXTRACTS OFSACCHAROMYCES CEREVISIAE

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Abstract
Alcohol dehydrogenase activities were determined in cell-free extracts of Saccharomyces cerevisiae with fusel oil-alcohols and other higher alcohols (including straight and branch-chain aliphatic alcohols, cinnamyl alcohol and phenethanol) as substrates. A fluorometric measurement of the formation of reduced coenzyme (NADH) was needed because of the necessity for increased sensitivity with the required use of very low concentrations of substrates. For the first time, dehydrogenase activities were measured in cell-free extracts for active-pentanol, n-hexanol and n-heptanol as substrates. Optimal molar concentration of the substrates was found to decrease with increasing carbon number. Activity measurements were made in extracts of yeasts grown under various conditions of oxygen induction and catabolite repression. Dehydrogenase activities for all substrates were higher in extracts of yeast grown aerobically as compared to those grown anaerobically. A comparison of the activities with the fusel oil-alcohols as substrates suggests a plurality of alcohol dehydrogenase activities in the last enzymic step in fusel oil formation.