DETECTION OF CYTOCHROME P4501A IN SEVERAL SPECIES USING ANTIBODY AGAINST A SYNTHETIC PEPTIDE DERIVED FROM RAINBOW-TROUT CYTOCHROME P4501A1

Induction of cytochrome P4501A (CYP1A) is being used increasingly as a biomarker to indicate exposure of organisms to environmental contamin ants such as some polycyclic and polychlorinated aromatic hydrocarbons . Measurement of CYP1A protein in wildlife would be facilitated by the use of a specific antibody that recognized the isozyme in several spe cies. In the present study, a polyclonal antibody targeted to CYP1A1 w as generated using a synthetic peptide corresponding to amino acids 27 7-294 of the trout enzyme as the antigen of immunization. Specificity of the resulting antibody was assessed by noncompetitive enzyme linked immunosorbent assay with several purified rat CYP isozymes and by imm unoblot analysis with liver microsomes from diverse species. The antib ody reacted strongly with the immunizing peptide and with purified rat cytochrome P4501A1 but did not react with rat CYP1A2, a closely relat ed isozyme, or with six other purified rat CYP proteins in enzyme-link ed immunosorbent assay. On immunoblots, the antibody recognized a sing le protein band in hepatic microsomes from the various mammal and fish species tested. Two protein bands were detected in liver microsomes f rom 3-methylcholanthrene-treated chickens. The results suggest that th e antigenic determinant to which the antibody binds is unique to CYP1A and is conserved in different species. Because of its specificity, th is anti-peptide antibody should be suitable as a probe to measure CYP1 A protein levels in wildlife.