Ref ID : 3983
Nancy S. Lamontagne, David F. Johnson, William B. Jakoby, and Chester E. Holmlund; A Secondary Alcohol Dehydrogenase from Tetrahymena furgasoni. J.Protozool. 29(3):401-405, 1982
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Dehydrogenase activity with hydroxysteroids has been observed in Tetrahymena furgasoni (formerly T. pyriformis strain W), and the enzyme responsible has been isolated from this organism. The purified dehydrogenase is active with a variety of steroid alcohols at apparent Km values ranging from 0.2 to 4.0 mM. The C-3 hydroxyl of ring A of the steroid nucleus is the preferred position of oxidation. However, a variety of other secondary alcohols are also substrates, with apparent Km values for 2-butanol, 2-pentanol, and cyclohexanol of 880, 1000, and 150 mM, respectively. With both steroidal and nonstroidal alcohols, NAD is the preferred co-substrate, although low activity with NADP is observed. Evidence is presented that the activity with secondary alcohols, whether steroidal or not, is the property of a single protein species.