The structural analysis of the O-glycans of the jacalin-bound rabbit immunoglobulin G.

Rabbit immunoglobulin G (IgG) is a sialoglycoprotein (2.4% carbohydrate), containing both N-glycolyl (Neu5Gc) and N-acetyl (Neu5Ac) neuraminic acids in a ratio of 87:13. A small fraction of rabbit IgG (about 25% of total IgG) bound to jacalin as demonstrated by affinity chromatography. The jacalin-bound rabbit IgG contained O-linked glycans which were liberated from the protein by beta-elimination and isolated. Two O-glycan structures were determined by 1H-NMR spectroscopy, as being Neu5Gc(alpha2-3)-Gal (beta31-3)-GalNAc-ol and Neu5Ac(alpha2-3)-Gal(beta1-3)-GalNAc-ol in a ratio of 83...n17.