HUMAN CYTOCHROME-P450 3A4 IS INVOLVED IN THE BIOTRANSFORMATION OF THEHERBICIDE 2,4-DICHLOROPHENOXYACETIC ACID

2,4-Dichlorophenoxyacetic acid (2,4-D) is one of the most frequently u sed herbicides and is an environmental pollutant. Evidence exists that 2,4-D exposure results in an increased risk for certain malignant dis orders such as nasal carcinoma and soft tissue sarcoma in humans and a nimals. The involvement of cytochrome P450 3A4 (CYP3A4), the major for m of monooxygenase enzyme in human liver, in the metabolism of 2,4-D w as studied using microsomal fractions and whole cells of Saccharomyces cerevisiae expressing cytochrome P450 3A4. 2,4-Dichlorophenol (2,4-DC P) 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.