Cytochrome superfamily (CYP)

Cytochromes are a broad superfamily of heme-containing proteins that facilitate essential redox reactions across various biological systems. The most clinically prominent subgroup, the Cytochrome P450 (CYP) enzymes, are primarily localized in the liver and are responsible for the oxidative metabolism of approximately 75% of known pharmaceutical agents [StatPearls: Cytochrome P450 Enzyme System, 2023]. Another critical member, Cytochrome c, serves as a vital electron carrier in the mitochondrial respiratory chain and acts as a pivotal signal for programmed cell death when released into the cytoplasm [UniProt: P99999]. While cytochromes themselves are rarely the primary therapeutic target of a drug—with the notable exception of fungal CYP51 targeted by azole antifungals—their interaction with drugs is a cornerstone of pharmacology [NCBI: Cytochrome P450, 2021]. Variation in cytochrome activity due to genetic polymorphisms or drug-mediated inhibition and induction can lead to significant changes in drug efficacy and safety profiles, often resulting in severe drug-drug interactions [FDA: Drug Development and Drug Interactions, 2020]. Consequently, understanding cytochrome-mediated metabolism is a mandatory component of the drug discovery and regulatory approval process to prevent adverse clinical outcomes [PubMed: 30121115].

Other names

CytochromesHemeproteinsCytochrome P450Cytochrome cCYP450 enzymes

Drugs typically interact with these proteins as substrates, inhibitors, or inducers; mechanisms include heme-coordinated oxidative metabolism, inhibition of fungal sterol synthesis (e.g., CYP51), or modulation of mitochondrial electron transfer.