Formation of 5α steroids by biotranformation involving the 5 α-reductase activity of Penicillium decumbens

Article abstract of DOI:10.1016/0039-128X(94)90020-5

The biotransformation of a series of Δ⁴-3-ketosteroids by the Penicillium decumbens ATCC 10436 has been investigated. Conversion to the 5α-dihydrosteroid was observed substrates of the androsterone and pregne series: the reaction is tolerant of non-polar substituents (Cl and CH₃) at C-4 of the substrate, but does not occur in the presence of a 4-hydroxyl group, or with additional unsaturation at the Δ¹ or Δ⁶ positions. A-nor, B-nor, 3-deoxy-, and 3,5-cycloandrostanes are not reduced, but 6-methylenestestosterone is converted to a 6-methylene-5α-dihydro derivative. Several biotransformations are reported which involve oxidoreductase activity at C-3 and/or C-17, either concomitant or independent of Δ⁴ reduction: the substrate specificity of the oxidoreductase processes has been examined and defined by the use of 3α-hydroxy, 3β-hydroxy, 3-keto, 17β-keto substituted steroids. In this way, the existence in P. decumbens of 3β-hydroxy-3-keto and 17β-hydroxy-17-keto oxidoreductases has been demonstrated.