title: Biosynthesis of lipid-linked oligosaccharides in embryonic liver. Formation of dolichyl pyrophosphate N-acetylglucosaminyl intermediates.
abstract: Liver microsomes from pig embryos synthesized dolichyl pyrophosphate N-acetylglucosamine and converted it to dolichyl pyrophosphate N,N'-diacetylchitobiose. N-acetylglucosaminyl transferase activity towards dolichol was about 2-fold greater in microsomes from embryonic liver than in microsomes from adult liver. A maximum level of conversion of dolichyl pyrophosphate N-acetylglucosamine to dolichyl pyrophosphate N,N'-diacetylchitobiose was achieved at 5 mM concentration of unlabelled UDP-N-acetylglucosamine, while this conversion was negligible at lower UDP-N-acetylglucosamine concentrations (0.1 and 0.5 mM). The level of dolichyl phosphate, assessed by the level of dolichyl pyrophosphate N-acetylglucosamine synthesis was 2-fold higher in microsomes from embryonic liver than that in microsomes from adult liver. Tunicamycin (1 microgram/ml) inhibited completely the formation of dolichyl pyrophosphate N-acetyl-glucosamine in embryonic liver microsomes, while the inhibitory effect of UMP (1 mM) was about 70%.
mesh_terms: D000367:Age Factors; D000818:Animals; D004288:Dolichol Phosphates / Q000378:metabolism; D005260:Female; D005964:Glucosyltransferases / Q000378:metabolism; D008099:Liver / Q000196:embryology; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism*; D017351:N-Acetylglucosaminyltransferases; D011103:Polyisoprenyl Phosphate Monosaccharides / Q000096:biosynthesis / Q000378:metabolism*; D011104:Polyisoprenyl Phosphate Oligosaccharides / Q000096:biosynthesis*; D011105:Polyisoprenyl Phosphate Sugars / Q000096:biosynthesis* / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D013552:Swine; D014415:Tunicamycin / Q000494:pharmacology; D014537:Uridine Diphosphate N-Acetylglucosamine / Q000378:metabolism; D014542:Uridine Monophosphate / Q000494:pharmacology
chemical_list: D004288:Dolichol Phosphates; D011103:Polyisoprenyl Phosphate Monosaccharides; D011104:Polyisoprenyl Phosphate Oligosaccharides; D011105:Polyisoprenyl Phosphate Sugars; D014415:Tunicamycin; D014537:Uridine Diphosphate N-Acetylglucosamine; C018439:N-acetylglucosaminylpyrophosphoryldolichol; C016418:dolichyl-diphosphate-di-N-acetylchitobiose; D014542:Uridine Monophosphate; D005964:Glucosyltransferases; D017351:N-Acetylglucosaminyltransferases; C023227:UDP-N-acetylglucosamine transferase