title: Synthesis and accumulation of mannose-containing glycopeptides in human fibroblast cells: possible separate pathways for neutral and acidic glycopeptides.
abstract: The normal human fibroblast, WI-38, was labelled with radioactive mannose and its incorporation, as well as the accumulation of acidic and neutral glycopeptides on the cell surface, was followed as a function of time. The transit time of newly made Pronase-released cell surface glycopeptides from their intracellular site of synthesis to the cell surface was slower in nongrowing cells than in a rapidly growing culture. When the surface glycopeptides were separated by high-voltage paper electrophoresis into neutral and acidic species, it was observed that the cell surface material was initially enriched with neutral glycopeptides. However, with time the relative proportion of acidic species increased so that by 3 h the ratio between the acidic and neutral species approached a constant value. Our data are consistent with the hypothesis that multiple pathways for asparagine-linked glycoprotein biosynthesis are possible.
mesh_terms: D000143:Acids; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism*; D006020:Glycopeptides / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D008358:Mannose / Q000378:metabolism*
chemical_list: D000143:Acids; D006020:Glycopeptides; D008358:Mannose