title: Elongation of N-acetyllactosamine repeats in diantennary oligosaccharides.
abstract: Glycosylated [Asn22]lysozyme has been shown to contain N-acetyllactosamine repeats when expressed in chinese hamster ovary (CHO) cells. We find that the major portion of N-acetyllactosamine repeats are associated with diantennary oligosaccharides. In Lec2 CHO cells, which are deficient in sialylation, glycosylated lysozyme is synthesized with increased contents of N-acetyllactosamine repeats terminating in beta-galactosyl residues. In the Lec2 cells and the parental CHO cell line, Pro 5, only a minor portion of the oligosaccharides in lysozyme are of the triantennary type. Previously, it has been shown that the synthesis of N-acetyllactosamine repeats in Asn-linked oligosaccharides is enhanced by an increase in the activity of the elongating beta-N-acetylglucosaminyl transferase and by the synthesis of beta-1,6-linked antennae. The results with glycosylated lysozyme suggest that glycoproteins bearing diantennary oligosaccharides can contain several N-acetyllactosamine repeats and that the number of the latter can be increased by decreasing the activity of the capping sialyl transferases.
authors.affiliation: Institut für Physiologische Chemie, Philipps-Universität Marburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hummel
authors.forename: H C
authors.initials: HC
authors.lastname: Hedrich
authors.forename: A
authors.initials: A
authors.lastname: Hasilik
mesh_terms: D000606:Amino Sugars / Q000737:chemistry*; D000818:Animals; D001216:Asparagine; D001426:Bacterial Proteins; D016466:CHO Cells; D002240:Carbohydrate Sequence; D006224:Cricetinae; D005998:Glycine; D006026:Glycoside Hydrolases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000378:metabolism; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009844:Oligosaccharides / Q000737:chemistry*
chemical_list: D000606:Amino Sugars; D001426:Bacterial Proteins; D009844:Oligosaccharides; C000458:N-acetyllactosamine; D001216:Asparagine; D006026:Glycoside Hydrolases; D009113:Muramidase; C106364:ENDOF2 protein, Flavobacterium meningosepticum; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D019158:N-Acetylneuraminic Acid; D005998:Glycine