Pluripotency of 17beta-hydroxysteroid dehydrogenase from the filamentous fungus Cochliobolus lunatus.
Cochliobolus lunatus 17beta-hydroxysteroid dehydrogenase (17beta-HSD) is pluripotent for several steroidal and nonsteroidal substrates. In the presence of NADPH the enzyme was found to reduce 3-keto groups of 4,5-dihydro steroids, 20-keto groups, and most efficiently, 17-keto groups of steroidal substrates. In addition, several quinones were accepted and found to be even better substrates as steroids due to their higher affinity for the enzyme-coenzyme complex and faster conversion of the enzyme-coenzyme-substrate complex into the corresponding products. As suggested by the competition studies quinones and 17-ketosteroids are converted by the same active center of the enzyme. For all tested substrates, the equilibrium ordered mechanism was established with NADPH binding first to the enzyme. According to our knowledge, the investigated 17beta-HSD is the first known fungal pluripotent enzyme of this type.
Zorko
M
M
Institute of Biochemistry, Medical Faculty, University of Ljubljana, Slovenia.
Gottlieb
H E
HE
Zakelj-Mavric
M
M
D015067:17-Hydroxysteroid Dehydrogenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001203:Ascomycota / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007700:Kinetics; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase