CYP3A4

CYP3A4 Full Name

cytochrome P450, family 3, subfamily A, polypeptide 4

CYP3A4 Introduction

CYP3A4 encodes a heme-containing thiolate monooxygenase and is one of the most significant members of the cytochrome P450 superfamily. This enzyme is predominantly expressed in adult liver and intestinal epithelial cells, accounting for approximately 30–50% of the total CYP protein content in the liver, making it the most abundant drug-metabolizing enzyme in the human body.

Figure 1. CYP3A4 is localized in the cellular photoplasmic endoplasmic reticulum. (Source: Zhang Y, et al. 2024)

The core function of CYP3A4 is to catalyze the oxidation of a wide range of structurally diverse compounds. Utilizing NADPH as a cofactor, it introduces hydroxyl groups into substrate molecules, enhancing their water solubility and facilitating excretion. This enzyme participates in the metabolism of more than 50% of commonly used clinical drugs, including statin lipid-lowering agents, benzodiazepine sedatives, calcium channel blockers, and various anticancer drugs. Beyond xenobiotics, CYP3A4 is also involved in the biotransformation of endogenous substances such as steroid hormones (e.g., testosterone, estradiol), bile acids, and long-chain fatty acids, thereby helping to maintain endocrine and lipid homeostasis.

Dysfunction of CYP3A4 is closely associated with various disease states. In oncology, the enzyme is frequently overexpressed in liver and breast cancers, leading to accelerated metabolism and clearance of chemotherapeutic agents, which can result in treatment failure or reduced toxicity. Conversely, genetic variants with low CYP3A4 activity may increase the risk of statin-induced myopathy. Additionally, CYP3A4 activity is low during childhood development and is susceptible to polypharmacy-related induction of resistance in the elderly. These physiological characteristics directly impact individualized medication safety in pediatric and geriatric populations. As such, CYP3A4 has become a central focus in precision medicine and clinical pharmacology research.

Alternate Names for CYP3A4

CYP3A4; cytochrome P450, family 3, subfamily A, polypeptide 4; HLP; CP33; CP34; CYP3A; NF-25; CYP3A3; P450C3; CYPIIIA3

• 1. Zhang Y, et al. CYP3A4 and CYP3A5: the crucial roles in clinical drug metabolism and the significant implications of genetic polymorphisms. PeerJ. 2024 Dec 5;12:e18636.
  2. Yuan X, et al. Transcriptional regulation of CYP3A4 by nuclear receptors in human hepatocytes under hypoxia. Drug Metab Rev. 2020 May;52(2):225-234.