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Substance Name: Cytochrome P 450
RN: 9035-51-2


  • A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.

Molecular Formula

  • Unspecified
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Links to Resources

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Names and Synonyms

MeSH Heading

  • Cytochrome P-450 Enzyme System


  • Cytochrome m
  • Cytochrome P 450
  • Cytochrome P-450-dependent monooxygenase
  • Cytochrome P450ii
  • P 450
  • Supermix

Systematic Name

  • Cytochrome P 450

Registry Numbers

CAS Registry Number

  • 9035-51-2

System Generated Number

  • 0009035512