title: Hydroxylation of steroids by Fusarium oxysporum, Exophiala jeanselmei and Ceratocystis paradoxa.
abstract: The potential of Fusarium oxysporum var. cubense UAMH 9013 to perform steroid biotransformations was reinvestigated using single phase and pulse feed conditions. The following natural steroids served as substrates: dehydroepiandrosterone (1), pregnenolone (2), testosterone (3), progesterone (4), cortisone (5), prednisone (6), estrone (7) and sarsasapogenin (8). The results showed the possible presence of C-7 and C-15 hydroxylase enzymes. This hypothesis was explored using three synthetic androstanes: androstane-3,17-dione (9), androsta-4,6-diene-3,17-dione (10) and 3α,5α-cycloandrost-6-en-17-one (11). These fermentations of non-natural steroids showed that C-7 hydroxylation was as a result of that position being allylic. The evidence also pointed towards the presence of a C-15 hydroxylase enzyme. The eleven steroids were also fed to Exophialajeanselmei var. lecanii-corni UAMH 8783. The results showed that the fungus appears to have very active 5α and 14α-hydroxylase enzymes, and is also capable of carrying out allylic oxidations. Ceratocystis paradoxa UAMH 8784 was grown in the presence of the above-mentioned steroids. The results showed that monooxygenases which effect allylic hydroxylation and Baeyer-Villiger rearrangement were active. However, redox reactions predominated.
authors.affiliation: Department of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaica.
authors.forename: Patrice C
authors.initials: PC
authors.lastname: Peart
authors.forename: Kayanne P
authors.initials: KP
authors.lastname: McCook
authors.forename: Floyd A
authors.initials: FA
authors.lastname: Russell
authors.forename: William F
authors.initials: WF
authors.lastname: Reynolds
authors.forename: Paul B
authors.initials: PB
authors.lastname: Reese
mesh_terms: D000731:Androstanes / Q000737:chemistry / Q000378:metabolism*; D001711:Biotransformation; D005093:Exophiala / Q000201:enzymology*; D005670:Fusarium / Q000201:enzymology*; D006900:Hydroxylation; D013250:Steroid Hydroxylases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000731:Androstanes; D013250:Steroid Hydroxylases