Cytochrome P450 3A4 (abbreviated<unk>  () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from the body. It is highly homologous to<unk> , another important<unk> enzyme. While many drugs are deactivated by<unk> , there are also some drugs which are activated by the enzyme. Some substances, such as some drugs and furanocoumarins present in grapefruit juice, interfere with the action of<unk> . These substances will therefore either amplify or weaken the action of those drugs that are modified by<unk> .<unk>  is a member of the cytochrome P450 family of oxidizing enzymes. Several other members of this family are also involved in drug metabolism, but<unk>  is the most common and the most versatile one. Like all members of this family, it is a hemoprotein, i.e. a protein containing a heme group with an iron atom. In humans, the<unk>  protein is encoded by the<unk>  gene. This gene is part of a cluster of cytochrome P450 genes on chromosome 7q22.1.
CYP3A4
CYP1A2
CYP2C19
CYP2D6
CYP3A5
CYP2C8
CYP2C9
CYP2J2