Cytochromes P450 (CYPs) are a family of enzymes containing heme as a cofactor that function as monooxygenases. "P450" is derived from the spectrophotometric peak at the wavelength of the absorption maximum of the enzyme (450 nm) when it is in the reduced state and complexed with carbon monoxide. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compounds, as well as for hormone synthesis and breakdown. In plants, these proteins are important for the biosynthesis of defensive compounds, fatty acids, and hormones. CYP enzymes have been identified in all kingdoms: animals, plants, fungi, bacteria, archaea and even in viruses. P450 oxidoreductase is an important cofactor for electron transfer from nicotinamide adenine dinucleotide phosphate (NADPH) to the 21-hydroxylase and 17_-hydroxylase/17,20-lyase and other cytochrome P450 enzymes.
Essential for multiple metabolic processes; chiefly among them are reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs, and xenobiotics. Most CYPs require a protein partner to deliver one or more electrons to reduce the iron. Cytochrome P450 oxidoreductase deficiency is a disorder of hormone production. This condition specifically affects steroid hormones, which are needed for normal development and reproduction. The hormonal changes associated with cytochrome P450 oxidoreductase deficiency can affect the development of the reproductive system, skeleton, and other parts of the body. These signs and symptoms are usually present at birth or become apparent in early childhood. Essential electron donor to all microsomal cytochrome P450 proteins including the steroid metabolizing CYP17A1, CYP19A1, and CYP21A2, as well as CYP51A1 and CYP26B1 which are involved in bone formation. Severe form of cytochrome P450 oxidoreductase deficiency is sometimes called Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis.
