Abstract

The separation of morphine and p-nitrophenol UDP-glucuronyltransferases from rat liver microsomes is described. Hepatic microsomes were solubilized using Emalgen 911, a non-ionic polyoxyethylene nonylphenyl ether, in the presence of glycerol and dithiothreitol, and chromatographed on DEAE-cellulose. The elution of three peaks of transferase activity was observed. One peak displayed transferase activity with p-nitrophenol as substrate, one exhibited activity with morphine as substrate, and one displayed activity with either substrate. Neither substrate inhibited the metabolism of the other. Michaelis constants determined for the partially purified preparations were similar to those obtained for native microsomes. These results demonstrate distinct and separate activities for the glucuronidation of p-nitrophenol and morphine in rat hepatic microsomes.