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Title: Testosterone 1 beta-hydroxylation by human cytochrome P450 3A4.

Authors: Krauser, Joel A; Voehler, Markus; Tseng, Li-Hong; Schefer, Alexandre B; Godejohann, Markus; Guengerich, F Peter

Published In Eur J Biochem, (2004 Oct)

Abstract: Human cytochrome P450 3A4 forms a series of minor testosterone hydroxylation products in addition to 6 beta-hydroxytestosterone, the major product. One of these, formed at the next highest rate after the 6 beta- and 2 beta-hydroxy products, was identified as 1 beta-hydroxytestosterone. This product was characterized from a mixture of testosterone oxidation products using an HPLC-solid phase extraction-cryoprobe NMR/time-of-flight mass spectrometry system, with an estimated total of approximately 6 microg of this product. Mass spectrometry established the formula as C(19)H(29)O(3) (MH(+) 305.2080). The 1-position of the added hydroxyl group was established by correlated spectroscopy and heteronuclear spin quantum correlation experiments, and the beta-stereochemistry of the added hydroxyl group was assigned with a nuclear Overhauser correlated spectroscopy experiment (1 alpha-H). Of several human P450s examined, only P450 3A4 formed this product. The product was also formed in human liver microsomes.

PubMed ID: 15373842 Exiting the NIEHS site

MeSH Terms: Animals; Baculoviridae/genetics; Chromatography, High Pressure Liquid; Cytochrome P-450 Enzyme System/metabolism*; Humans; Hydroxylation; Magnetic Resonance Spectroscopy; Mass Spectrometry; Microsomes, Liver/drug effects; Microsomes, Liver/enzymology*; NAD/metabolism; NADP/metabolism; Oxidation-Reduction; Testosterone/metabolism*

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