Cytochrome P450, or CYP genes, constitute one of the largest families of genes, with representatives in virtually all living organisms. P450 enzymes are heme-thiolate proteins best known for their monooxygenase role, catalyzing the transfer of one atom of molecular oxygen to a substrate and reducing the other to water. The CYP4 clan includes D. melanogaster CYP4, 311-313, 316 and 318 family genes. Few CYP4 enzymes have been characterized, though some CYP4 genes are inducible by xenobiotics. (Adapted from
FBrf0248421.)