Characterization of mannose-labeled glycopeptides from human diploid cells and their growth-dependent alterations.
Mannose-labeled glycopeptides were prepared from human diploid fibroblasts harvested by brief pronase digestion. Combined use of endo-beta-N-acetylglucosaminidase H and D converted most of the mannose-label into arrays of oligosaccharides. They were separated by paper chromatography and were characterized by Sephadex G-25 column chromatography, by affinity column chromatography on concanavalin A-Sepharose, and by successive digestion with alpha-mannosidase and beta-mannosidase. The results indicated that mannose residues existed as clusters of various sizes, which we refer to as "oligomannosyl cores". The large oligomannosyl cores (approximately 7 to 8 mannosyl residues) were predominant in the glycopeptides from growing cells and were preferentially associated with neutral glycopeptides, similar to Unit A glycopeptides of thyroglobulin (mannose-N-acetylglucosamine unit). In glycopeptides from nongrowing cells, the ratio of the large oligomannosyl cores decreased, accompanying the increase of a small oligommanosyl core consisting of 3 mannosyl residues. The small core was preferentially associated with acidic glycopeptides.
D000118:Acetylglucosaminidase; D002455:Cell Division; D002460:Cell Line; D004171:Diploidy; D005347:Fibroblasts; D006020:Glycopeptides / Q000096:biosynthesis; D006801:Humans; D008358:Mannose / Q000378:metabolism*; D008361:Mannosidases; D009844:Oligosaccharides / Q000032:analysis
D006020:Glycopeptides; D009844:Oligosaccharides; D008361:Mannosidases; D000118:Acetylglucosaminidase; D008358:Mannose