Microsomal glucuronidation of a quaternary ammonium compound, 3-hydroxyphenyltrimethylammonium

3-Hydroxyphenyltrimethylammonium (HPTMA) is glucuronidated in vitro by rat liver microsomes supplemented with UDP-glucuronic acid. Little reaction occurred in the postmicrosomal supernatant fraction. Triton X-100 doubled the maximal velocity for the microsomecatalyzed reaction without altering the apparent KM value for HPTMA. This is the first report of glucuronidation of a quaternary ammonium compound in vitro.