Study of the sugar chains of recombinant human amyloid precursor protein produced by Chinese hamster ovary cells

The N- and O-glycans of recombinant amyloid precursor protein (APP), purifi ed from Chinese hamster ovary cells transfected with the human 695-amino ac id form of APP, were separately released by hydrazinolysis under different conditions. The reducing ends of the released N- and O-glycans were reduced with (NaBH4)-H-3 and derivatized with 2-aminobenzamide (2AB), respectively . After acidic N-glycans were obtained by anion-exchange column chromatogra phy, these were converted to neutral oligosaccharides by sialidase digestio n, demonstrating that their acidic nature was entirely due to sialylation. The sialidase-treated N-glycans were then fractionated by lectin column chr omatography and their structures were determined by linkage-specific sequen tial exoglycosidase digestion. These results demonstrated that recombinant APP has bi- and triantennary complex type N-glycans with fucosylated and no nfucosylated trimannosyl cores. In a similar fashion, the 2AB-labeled O-gly cans derived from APP were determined to be mono- and disialylated core typ e 1 structures. Taken together, these results indicate that recombinant APP has sialylated bi- and triantennary N-glycans with fucosylated and nonfuco sylated cores and sialylated O-glycans with core type 1 structures. (C) 199 9 Elsevier Science B.V. All rights reserved.