Growth-associated glycosylation of transferrin secreted by HepG2 cells.
Growth-associated alterations in the oligosaccharide structures of transferrin secreted by HepG2 cells were examined by concanavalin A-crossed affinoimmuno-electrophoresis. Slowly dividing, confluent cultures produced transferrin with a approximately 4.5-fold greater proportion of biantennary complex-type oligosaccharides than rapidly dividing, subconfluent cultures. The activity of N-acetylglucosaminyltransferase V (GlcNAc-T V) and galactosyltransferase were measured in cell extracts from subconfluent and confluent cultures. While the activity of galactosyltransferase remained relatively constant, the activity of GlcNAc-T V was approximately 3.2-fold lower in confluent cultures than in subconfluent cultures. These results suggest that the growth-associated alteration in the oligosaccharides of transferrin is due, at least in part, to the regulation of GlcNAc-T V activity.
Hahn
T J
TJ
Department of Chemical Engineering, Stanford University, California 94305-5025.
Goochee
C F
CF
D002240:Carbohydrate Sequence; D006528:Carcinoma, Hepatocellular; D002455:Cell Division; D002999:Clone Cells; D005700:Galactosyltransferases / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007700:Kinetics; D008113:Liver Neoplasms; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases / Q000378:metabolism; D013997:Time Factors; D014168:Transferrin / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D014168:Transferrin; D005700:Galactosyltransferases; D017351:N-Acetylglucosaminyltransferases; C052254:alpha-1,6-mannosylglycoprotein beta 1,6-N-acetylglucosaminyltransferase