Cytochrome P450 3A43 (CYP3A43)

CYP3A43 encodes a member of the cytochrome P450 superfamily of enzymes. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q21.1. Alternate splicing of this gene results in three transcript variants encoding different isoforms.The deduced protein is 76%, 76%, and 72% identical to CYP3A4, CYP3A5, and CYP3A7, respectively. Real-time PCR in 10 different livers revealed that CYP3A43 is expressed at 0.1% and 2% of the levels of CYP3A4 and CYP3A5.SDS-PAGE and Western blot analysis showed expression of an approximately 55-kD protein. Functional analysis indicated that, under appropriate conditions, CYP3A43 exhibits low but reproducible testosterone 6-beta-hydroxylase activity.