cytochrome P450 family 3 subfamily A member 43(CYP3A43) Homo sapiens This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. The encoded protein has a low level of testosterone hydroxylase activity, and may play a role in aging mechanisms and cancer progression. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q21.1. Alternate splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Jul 2013]