Structure and stereochemistry of products of hydroxylation of human steroid hormones by a housefly cytochrome P450 (CYP6A1)

Article abstract of DOI:10.1002/mrc.1767

The structure and stereochemistry of nine steroid metabolites isolated in quantities ranging from 0.15 to 1.8 mg were determined using a variety of NMR techniques, including heteronunclear multiple bond correlation (HMBC) using broadband adiabetic ¹³C pulses and phase-sensitive data presentation. Testosterone, and rostenedione and progesterone were oxidized with housefly cytochrome P450 6A1 enzyme reconstituted in vitro with housefly NADPH cytochrome P450 reductase and cytochrome b₅. NMR analysis in CD₃OD using a modified HMBC sequence as well as 2D heteronuclear single quantum correlation (HSQC), COSY and nuclear Overhauser and exchange spectroscopy (NOESY), combined with a detailed analysis of J couplings showed that hydroxylation occurs exclusively on the β-face of the steroids, at positions 2, 12, and 15. Copyright