Transformation of dehydroepiandrosterone and pregnenolone by Mucor piriformis

Abstract

The mode of transformation of dehydroepiandrosterone (I, 3β-hydroxyandrost-5-en-17-one) and pregnenolone (II, 3β-hydroxypregn-5-en-20-one) was studied using Mucor piriformis. Biotransformation products formed from I were 3β, 17β-dihydroxyandrost-5-ene (Ia), 3β-hydroxyandrost-5-ene-7,17-dione (Ib), 3β,17β-dihydroxyandrost-5-en-7-one (Ic), 3β,7α-dihydroxyandrost-5-en-17-one (Ie). Biotransformation products formed from compound II were 3β,7α-dihydroxypregn-5-en-20-one (IIa) and 3β,7α,11α-trihydroxypregn-5-en-20-one (IIb). The organism did not carry out isomerization of the 5-en-3β-ol to a 4-en-3-one system in the steroid molecules tested. In addition, it failed to carry out 14α-hydroxylation possibly because of the lack of a 4-en-3-one system in I and II, and stereospecific hydroxylation at the C-7 position in I and II.