Postnatal changes in N-linked oligosaccharides of glycoproteins in rat liver.
[3H]Mannose-labelled glycopeptides in the slices of livers from neonatal and 1-, 2-, 3- and 5-week-old rats were characterized by column chromatographies on Sephadex G-50 and concanavalin A-Sepharose and by endo-beta-N-acetylglucosaminidase H digestion. The proportion of complex-type glycopeptides was increased with time until 2 weeks post partum and then returned to the neonatal level. This was mainly due to the increased proportion of concanavalin A-bound (biantennary) species. These changes were accompanied by consistent changes in the activities of processing enzymes in liver microsomal fraction, especially of N-acetylglucosaminyltransferase I. Complex-type glycopeptides from neonatal and 2- and 5-week-old rat livers were further characterized by column chromatographies on Bio-Gel P-6 and DE 52 DEAE-cellulose in combination with neuraminidase digestion. No significant difference was found between concanavalin A-bound species from neonatal liver and those from liver 5 weeks post partum, most of which were sialylated. Concanavalin A-bound species 2 weeks post partum were comparatively smaller in size and less sialylated. On the other hand, there was no significant difference among concanavalin A-unbound species from the three different sources, most of which were sialylated. Since glycoproteins from regenerating rat liver also contain a higher proportion of complex-type oligosaccharides, as previously reported, such changes in N-linked oligosaccharides of glycoproteins may be related to control of the growth of liver cells.
Department of Biochemistry, St. Marianna University School of Medicine, Kawasaki, Japan.
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Kato
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Oda-Tamai
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N
Akamatsu
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D005260:Female; D005959:Glucosidases / Q000378:metabolism; D006020:Glycopeptides / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D009844:Oligosaccharides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D006020:Glycopeptides; D006023:Glycoproteins; D009844:Oligosaccharides; D005959:Glucosidases