STUDIES ON MANNOSYL GLYCOPEPTIDES FROM NORMAL AND TRANSFORMED-CELLS

Mannose-labeled glycopeptides were prepared by exhaustive pronase digestion of the cell trypsinate (cell-surface) and cellular material of normal and polyoma-transformed baby hamster kidney cells which were grown in a medium containing [3H]mannose When mannosyl oligosaccharides released from the glycopeptides by digestion with endoglycosidases were comparatively analyzed by paper chromatography, there was no qualitative difference between the oligosaccharides from normal cells and those from transformed cells. Furthermore, their chromatographic patterns were the same as those obtained from cellular glycopeptides of 3Y1B cells (rat fibroblasts) and those previously obtained from human diploid cells. Therefore, the oligomannosyl backbone structures of the sugar chains of cultured mammalian fibroblasts seem to be very similar.Substantial amounts of the mannosyl oligosaccharides were isolated from 3Y1B cells and analyzed by several procedures. The oligosaccharides generally appear to have the structure (Manα)Man βGlcNAc(2 ≦n≦ 8). The finding that (Manα)8ManβGlcNAc which was the largest oligosaccharide, is apparently identical in size to the largest oligosaccharide released from Unit A glycopeptide of thyroglobulin suggests that a common regulatory mechanism is involved in the biosynthesis of the sugar chains of many mannosyl glycoproteins. © 1979 By The Journal Of Biochemistry.