Hydroxyl groups at C-3 and at C-17 of the unnatural enantiomer, ent-androsta-5,9(11)-diene-3β,17β-diol are oxidised by cholesterol oxidase from Rhodococcus erythropolis

The ent-androsta-4,9(11)-diene-3β,17β-diol 1b and ent-androsta-5,9(11)-diene-3β,17β-diol 2b prepared from chiral dione 3, were oxidised by cholesterol oxidase with kinetic parameters close to those of the natural steroids 1a and 2a. In the preparative oxidation the final product was ent-androsta-4,9(11)-diene-3,17-dione 5. So the enzyme catalysed the oxidation of the hydroxyl groups at C-3 and C-17, whereas the natural enantiomers were only oxidised at C-3.