| Abstract: | Two major and two minor forms of dihydrodiol dehydrogenase with similar molecular weights of around 36000 were purified from monkey liver cytosol. All the forms oxidized trans-dihydrodiols of benzene and naphthalene and reduced aromatic aldehydes, but showed differences in charge, specificity for other substrates and inhibitor sensitivity. One major (pI 8.7) and one minor (pI 7.9) form of the enzyme exhibited high activity for alicyclic alcohols and sensitivity to o-phenanthroline. The other major form (pI 6.2) oxidized 3 alpha-hydroxysteroids and was inhibited by dexamethasone and indomethacin, whereas the other minor form (pI 5.8) showed high reductase activity for aldehydes including D-glucuronate and sensitivity to barbital and sorbinil, and cross-reacted with human aldehyde reductase. The results indicate that the multiple forms of monkey liver dihydrodiol dehydrogenase are indanol dehydrogenases, 3 alpha-hydroxysteroid dehydrogenase and aldehyde reductase. |
