Growth-dependent alterations in oligomannosyl cores of glycopeptides.

Mannose-labeled glycopeptides from the surface of growing and nongrowing human diploid cells (KL-2) were separated into neutral glycopeptides and acidic glycopeptides by paper electrophoresis. Growth-dependent alterations occurred in oligomannosyl cores in the neutral glycopeptides; namely, the neutral glycopeptides from the surface of growing cells were more resistant to endo-beta-N-acetylglucosaminidase D but were more susceptible to alpha-mannosidase (EC 3.2.1.24; alpha-D-mannose mannohydrolase) than those derived from the surface of nongrowing cells. Another growth-dependent change was found when the endoglycosidase-resistant material from acidic glycopeptides was compared by paper electrophoresis at pH 1.9. The material from the surface of nongrowing cells contained a component that was absent or greatly reduced in growing cells.