Substrate specificity of nine NAD(+)-dependent alcohol dehydrogenases in Aspergillus nidulans.

In Aspergillus nidulans three alcohol dehydrogenases (ADHs) have been described. ADHI is induced by ethanol and is the physiological enzyme of ethanol utilization, ADHII has not been attributed a function but is repressed by ethanol. The ALCR regulatory protein acts positively to induce ADHI, and negatively in its control of ADHII. ADHIII is specifically induced by anaerobic stress. We have characterized the substrate specificity of these three enzymes by looking at their staining profile on polyacrylamide gels with a range of alcohols. In addition to these enzymes we have observed six other NAD(+)-dependent ADHs, two of which, propan-2-ol dehydrogenase and pentan-2-ol dehydrogenase, share similar control with ADHII. The inducibility of these enzymes with some alcohols has also been investigated. The profile of ADHs with NADP+ as an electron acceptor is also reported.