%0 Journal Article %A D. M. JERINA %A P. M. DANSETTE %A A. Y. H. LU %A W. LEVIN %T Hepatic Microsomal Epoxide Hydrase: a Sensitive Radiometric Assay for Hydration of Arene Oxides of Carcinogenic Aromatic Hydrocarbons %D 1977 %J Molecular Pharmacology %P 342-351 %V 13 %N 2 %X A rapid, highly sensitive thin-layer chromatographic assay is described for measurement of epoxide hydrase activity with 11 substrates, including alkene oxides, K-region arene oxides, and non-K-region arene oxides. The highest and lowest specific activities observed were for phenanthrene 9,10-oxide (39 nmoles of product per minute per milligram of protein) and dibenzo[a,h]anthracene 5,6-oxide (0.4 nmole of product per minute per milligram of protein) with liver microsomes from untreated rats. The most sensitive assay for epoxide hydrase activity was the hydration of benzo[a]pyrene 4,5-oxide. Prior treatment of rats with phenobarbital resulted in a 1.7-2.7-fold increase in the rate of hydration for the 11 substrates, whereas 3-methylcholanthrene treatment increased the epoxide hydrase activity approximately 1.3-1.9-fold. %U https://molpharm.aspetjournals.org/content/molpharm/13/2/342.full.pdf