Do lymphoblast-expressed microsomes contain endogenous Phase II enzymes?
We have limited information on the Phase II activities of lymphoblast microsomes. For glucuronosyl transferase activity and sulfotransferase activity see: C.L. Crespi, J.D. Altman and M.A. Marletta. “Xenobiotic Metabolism and Mutation in a Human Lymphoblastoid Cell Line”, Chem.-Biol. Interactions (1985) 53, 257-272. An additional 12% of the benzo(a)pyrene metabolites produced by the native CYP1A1 present in the parent AHH-1 cell line were released by treatment with beta-glucuronidase. However, no direct conjugation of p-nitrophenol, 3-hydroxybenzo(a)pyrene or 9-hydroxybenzo(a)pyrene was observed using 14C-UDPGA (<0.1 pmole per million cell minutes). This suggests that glucuronosyl transferase(s) may be present in control microsomes (455101 (Old M101A)) but, at a very low level. Treatment with sulfatase did not result in the release of additional benzo(a)pyrene metabolites. Since the sulfotransferases are soluble enzymes there should be no activity in microsomes. Lymphoblast cells conta
