Human cytochrome P450 has been used in a study to investigate non-viral environmental risk factors for nasopharyngeal carcinoma. Human cytochrome P450 has also been used in a study to investigate the dynamics and hydration of the active sites of mammalian cytochromes.

Cytochrome P450 enzymes are heme containing monooxygenases which are found primarily in the mammalian liver. They catalyze the oxidative metabolism of xenobiotics. This metabolism is the initial step in the biotransformation and elimination of a wide variety of drugs and environmental pollutants from the body. This product has a molecular mass of approximately 58 kDa. Amiodarone, furafylline, and cimetidine are inhibitors, whereas tobacco, insulin, and omeprazole are inducers of the enzyme. The isozyme CYP1A2 is a major pathway for the 6-hydroxylation of melatonin in vivo. This isozyme also catalyzes the 5-hydroxylation of thiabendazole.

Cytochrome P450 is a heterogeneous family of isozymes whose primary function is to oxidize small molecules, both as a function of intermediary metabolism (e.g., fatty acids) and to detoxify exogenous compounds (drugs or toxins). Some isoforms have narrow substrate specificity, while others are promiscuous. The CYP1A1 isoform catalyzes 7-deethylation of ethoxyresorufin. Cytochrome P450 (CYP) plays an important role in detoxifying xenobiotics, cellular metabolism and homeostasis. One of the main mechanisms of drug-drug interactions is the induction or inhibition of these enzymes. CYP enzymes are transcriptionally activated by a variety of xenobiotics and by endogenous substrates via receptor-dependent pathways. Inhibition of these enzymes is a major factor in metabolism-based drug-drug interactions, and many chemotherapeutic medications can cause drug interactions by either inhibiting or inducing the cytochrome p450 enzyme system.

Microsomes containing recombinant human CYP1A2, recombinant rabbit NADPH-P450 reductase, and cytochrome b₅.

Solution in 100 mM potassium phosphate buffer_, pH 7.4.