Galactosyltransferase-dependent sialylation of complex and endo-N-acetylglucosaminidase H-treated core N-glycans in vitro.
Purified beta-N-acetylglucosaminide beta(1-4)galactosyltransferase and partially purified beta-galactoside alpha(2-6)-sialyltransferase were used to elongate and terminate glycan chains of agalacto-ovalbumin and endo-beta-N-acetylglucosaminidase H-treated yeast invertase in vitro. In the presence of both transferases, 0.1 mol sialic acid was incorporated per mol agalacto-ovalbumin within 24 h. Evidence is presented to show that purification of the galactosylated intermediate increases the efficiency of sialylation. Incorporation of sialic acid into endo-beta-N-acetylglucosaminidase H-treated oligomannose glycoproteins may be useful for in vivo stabilization of these glycoproteins by preventing uptake in liver or reticuloendothelial cells.
D000818:Animals; D002645:Chickens; D005700:Galactosyltransferases / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006596:Hexosaminidases / Q000378:metabolism; D066298:In Vitro Techniques; D010047:Ovalbumin / Q000378:metabolism; D012441:Saccharomyces cerevisiae; D012799:Sialyltransferases / Q000378:metabolism*; D014166:Transferases / Q000378:metabolism*; D043324:beta-Fructofuranosidase
D006023:Glycoproteins; D010047:Ovalbumin; D014166:Transferases; D005700:Galactosyltransferases; D012799:Sialyltransferases; D006026:Glycoside Hydrolases; D006596:Hexosaminidases; D043324:beta-Fructofuranosidase