[Chromatographic method of determining membrane epoxide hydrolase activity].

A new method for determination of the activity of epoxide hydrolase (EC 3.3.2.3), an enzyme of the 2nd phase of the system of drug metabolism, in rat liver microsomes was developed. 9,10-Epoxy-9,10-dihydrophenanthrene was used as a substrate. The quantitative determination of 9,10-dioxy-9,10-dihydrophenanthrene was performed according to the method of the internal standard by HPLC in aqueous a cetonitrile on octylsilica gel with fluorescent detection. 1-Naphthol was used as the internal standard. The method is simple and requires no preliminary extraction of the sample and preparation of the derivatives. It is highly sensitive and rapid: the time of the chromatographic analysis is not more than 3 minutes. The error does not exceed 5 per cent.