A Comparison of Benzo(A)Pyrene-4,5-Epoxide Hydrase Activity in Hamster Embryo Cells,Hepatocytes and Livers Using High-Pressure Liquid Chromatography

Abstract

The benzo(a)pyrene-4,5-epoxide (BP-4,5-epoxide) hydrase activities of intact hamster hepatocytes and embryo cells, and homogenates of these cells as well as of adult liver are compared. The product of the epoxide hydrase (EH) reaction, trans-4,5-dihydro-4,5-dihydroxybenzo(a)pyrene (BP-4,5-diol), was isolated by high-pressure liquid chromatography (HPLC) with a Waters Bondapak C₁₈/Corasil column and acetonitrile-water as the mobile phase. Using this procedure to determine BP-4,5-epoxide hydrase activity in intact cells, it was found that 266 nmoles of BP-4,5-diol/10⁶ cells were produced by hepatocytes while no diol formation was detected with embryo cells. EH activity in the intact hepatocytes was 8-fold greater than in hepatocyte homogenates.