Synthesis of N- and O-linked glycopeptides in oviduct membrane preparations.
A hen oviduct membrane preparation that catalyzes both the N- and O-glycosylation of exogenous acceptor peptides was used to examine the possible involvement of lipid intermediates in enzymatic O-glycosylation. The results indicate that, under a variety of experimental conditions in which the dolichol-linked saccharides involved in N-glycosylation are readily observed, no lipid-linked intermediates for O-glycosylation could be detected. Whereas N-glycosylation is abolished by tunicamycin treatment and stimulated by dolichol phosphate addition, O-glycosylation is unaffected by such treatments. Further, the results of subcellular fractionation of oviduct membranes suggest that N-acetylgalactosaminyl:polypeptide transferase is localized primarily in membranes derived from the smooth endoplasmic reticulum and Golgi apparatus. This is in contrast to the subcellular site of N-glycosylation, which has previously been shown to be primarily the rough endoplasmic reticulum. These findings are discussed in relation to the function of dolichol phosphate in protein glycosylation.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002645:Chickens; D004288:Dolichol Phosphates / Q000378:metabolism; D005260:Female; D006020:Glycopeptides / Q000096:biosynthesis*; D006155:Guanosine Diphosphate Mannose / Q000378:metabolism; D007700:Kinetics; D008565:Membrane Proteins / Q000096:biosynthesis*; D010057:Oviducts / Q000378:metabolism*; D014415:Tunicamycin / Q000494:pharmacology
D004288:Dolichol Phosphates; D006020:Glycopeptides; D008565:Membrane Proteins; D014415:Tunicamycin; D006155:Guanosine Diphosphate Mannose