Cytochromes P450 (CYPs) belong to the superfamily of proteins containing a
heme cofactor and, therefore, are
hemoproteins. CYPs use a variety of small and large
molecules as
substrates in enzymatic reactions. They are, in general, the terminal oxidase enzymes in
electron transfer chains, broadly categorized as
P450-containing systems. The term
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
CO.