Localization of the enzyme system for glycosylation of proteins via the lipid-linked pathway in rough endoplasmic reticulum.
A crude preparation of microsomal membranes (postmitochondrial supernatant fraction) from the magnum portion of the hen oviduct was further subfractionated using a discontinuous sucrose gradient. Preparations of purified smooth surfaced membranes and rough endoplasmic reticulum, characterized by electron microscopy and nucleic acid content, were isolated. The enzymes involved in formation of mannose-containing glycoproteins via the lipid-linked pathway were shown to be localized in the rough endoplasmic reticulum. In contrast, a galactosyltransferase that catalyzed transfer of galactose to asialo-agalacto-orosomucoid was localized in the smooth membrane fraction. There was no evidence for the involvement of lipid intermediates in the galactosyl transfer observed in this fraction.
D000818:Animals; D002645:Chickens; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis*; D006155:Guanosine Diphosphate Mannose / Q000378:metabolism; D006602:Hexosyltransferases / Q000378:metabolism; D008566:Membranes / Q000378:metabolism; D008861:Microsomes / Q000378:metabolism; D010057:Oviducts / Q000378:metabolism; D011105:Polyisoprenyl Phosphate Sugars / Q000378:metabolism
D006023:Glycoproteins; D011105:Polyisoprenyl Phosphate Sugars; D006155:Guanosine Diphosphate Mannose; D006602:Hexosyltransferases