PURIFICATION AND PRELIMINARY CHARACTERIZATION OF ALCOHOL-DEHYDROGENASE FROM ASPERGILLUS-NIDULANS

Aspergillus alcohol dehydrogenase is produced in response to growth in the presence of a wide variety of inducers; the most effective inducers are short-chain alcohols and ketones, e.g., butan-2-one and propan-2-ol. The enzyme can be readily extracted from fresh or freeze-dried cells, and it can be purified to homogeneity on Blue Sepharose in a single step, by using specific elution with NAD+ and pyrazole. The pure enzyme has MW 290,000 by electrophoresis or gel filtration; it is a homopolymer with subunit MW 37,500 by electrophoresis in sodium dodecyl sulfate; its amino acid composition corresponds to MW 37,900, and the native enzyme contains 1 Zn atom per subunit. The enzyme is NAD-specific, and it has a wide substrate activity in the forward and reverse reactions; its activity profile is not identical with those of other alcohol dehydrogenases.