xenob io t ic a , 1998, vol . ... sulphoxide (DMSO) for concentrations up to 1000 l m and in 10 l l DMSO for higher concentrations), 10 mm MgCl # ,2mm EDTA, 55 mm phosphate buåer, pH 7± 4, and 0± 5±3 mg microsomal protein in a ®nal volume of 1 ml. ... Xenobiotica, 26, 681±693. ...