[5] The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.

It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics.

Most studies suggesting any non-overlapping metabolic functions apart from CYP3A4 were limited to small differences in metabolites produced from drugs which themselves were still substrates of CYP3A4.

It was proposed that clobetasol propionate differentially occupied the binding site of CYP3A5 compared to CYP3A4 (which would later become validated with subsequent studies).

It is most common among individuals native to Sub-Equatorial Africa, though the mutation also occurs at low frequencies in other populations.

[14][15] Global distribution of the CYP3A5 alleles:[15] Click on genes, proteins and metabolites below to link to respective articles.