Epoxide hydrolase expression in human and rodent established cell lines

Four human, four hamster and three mouse established cell lines have been analysed for epoxide hydrolase activity, and these have been compared with activities of human and mouse tissue preparations. Activities expressed by the cell lines, using styrene oxide as substrate, varied between less than 0.005 and 0.44 nmol/min per mg total cellular protein. Human liver and human kidney expressed 12.2 nmol and 2.7 nmol/min per mg total protein respectively. Antibodies prepared against purified human- and mouse-liver epoxide hydrolase enzymes were used to characterize the enzyme in the cell lines. Antihuman antibody was able to inactivate and precipitate enzyme in human cell lines and partially inactivate and precipitate hamster enzymes. It was much less effective against mouse cell lines. Antimouse antibody was able to precipitate mouse enzymes and partially precipitate hamster enzymes but did not precipitate human enzymes. These data may reflect evolutionary divergence of the three species.