Human cytochrome P450 3A4 is involved in the biotransformation of the herbicide 2,4-dichlorophenoxyacetic acid.

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most frequently used herbicides and is an environmental pollutant. Evidence exists that 2,4-D exposure results in an increased risk for certain malignant disorders such as nasal carcinoma and soft tissue sarcoma in humans and animals. The involvement of cytochrome P450 3A4 (CYP3A4), the major form of monooxygenase enzyme in human liver, in the metabolism of 2,4-D was studied using microsomal fractions and whole cells of Saccharomyces cerevisiae expressing cytochrome P450 3A4. 2,4-Dichlorophenol (2,4-DCP) was identified as the only product of metabolism by TLC followed by NMR and IR spectroscopy and a turnover of 0.13 nmol 2,4-DCP/min/nmol P450 was observed.