title: Transformation of 4-androsten-3,17-dione by growing cultures and cell extracts of Clostridium paraputrificum.
abstract: Growing cultures of Clostridium paraputrificum transformed 4-androsten-3,17-dione to 3 alpha-hydroxy-5 beta-androstan-17-one in a sequential manner with 5 beta-androstan-3,17-dione as an intermediate. The addition of 1.5 mM menadione to log-phase cultures which had formed 5 beta-androstan-3,17-dione resulted in a partial reoxidation of this steroid to 4-androsten-3,17-dione. However, this treatment also resulted in transient inhibition of culture growth. Resumption of growth was accompanied by complete reduction of 4-androsten-3,17-dione to 5 beta-androstan-3,17-dione. Cell extracts of C. paraputrificum were capable of carrying out these reductive transformations in the absence of added cofactors. However, Sephadex G-25 treated extracts required NADH or NADPH for these reactions. A flavin nucleotide, either FAD (plus NADH or NADPH) or FMN (plus NADH) was highly stimulatory for 4-androsten-3,17-dione reduction to 5 beta-androstan-3,17-dione. NADH was the preferred reduced pyridine nucleotide for reduction of the C4-C5 double bond, while time-course measurements suggested that NADPH was the preferred donor for reduction of the 3-keto group.
mesh_terms: D000731:Androstanes / Q000378:metabolism*; D000735:Androstenedione / Q000378:metabolism*; D002474:Cell-Free System; D003013:Clostridium / Q000254:growth & development / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D014812:Vitamin K / Q000494:pharmacology
chemical_list: D000731:Androstanes; D009243:NAD; D014812:Vitamin K; D000735:Androstenedione