Title: cytochrome P450
Long Title: IUPAC Gold Book - cytochrome P450
DOI: 10.1351/goldbook.CT06821
Status: current

Definition
Member of a superfamily of heme-containing monooxygenases involved in xenobiotic metabolism, cholesterol biosynthesis, and steroidogenesis, in eukaryotic organisms found mainly in the endoplasmic reticulum and inner mitochondrial membrane of cells. ‘P450’ refers to a feature in the carbon monoxide absorption difference spectrum at \(450\ \rm{nm}\) caused by the presence of a thiolate in the axial position of the heme opposite to the carbon monoxide ligand.

Related Terms
- biosynthesis: https://goldbook.iupac.org/terms/view/B00665
- membrane: https://goldbook.iupac.org/terms/view/MT06878
- metabolism: https://goldbook.iupac.org/terms/view/M03858
- xenobiotic: https://goldbook.iupac.org/terms/view/XT06755

Source
- PAC, 2004, 76, 1033. 'Glossary of terms used in toxicokinetics (IUPAC Recommendations 2003)' on page 1048 (https://doi.org/10.1351/pac200476051033)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/CT06821/html
- json: https://goldbook.iupac.org/terms/view/CT06821/json
- xml: https://goldbook.iupac.org/terms/view/CT06821/xml

Citation: Citation: 'cytochrome P450' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.CT06821
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Accessed: 2026-07-25T22:39:26+00:00