Abstract
We investigated the structural changes in asparagine-linked sugar chains of rat sciatic nerve glycoproteins during aging and reported previously that high-mannose-type sugar chains were abundant in younger animals, whereas two sialylated/sulfated oligosaccharides, OIBA1 and OIBA2, increased during maturation. We investigated further on the sugar chains increased by aging and found that there were several oligo-sialylated sugar chains (referred to as OIBA-3. OIBA-4, and OIBA-5). The common structure of these sugar chains was determined to be a bi-antennary complex-type oligosaccharide; Galβ1-4GlcNAcβ1-2-Manα1-6(Galβ1-4GlcNAcβ1-2Manα1-3)Manβ1-4GlcNAcβ1-4(Fucα1-6)GlcNAc. A sulfate residue linked to the 6-O-GlcNAc on the C3 antenna. The difference among them was revealed to be sialic acid contents. We analysed the structures of these sugar chains by exo-glycosidase digestion, HPLC analysis, and MALDI-TOF-MS. The oligosaccharide structures of the OIBA familiy were determined as follows; (Sia)0-3-Galβ1-4GlcNAcβ1-2-Manα1-6((Sia)0-1-Galβ1-4(SO4-6)GlcNAcβ1-2Manα1-3)Manβ1-4GlcNAcβ1-4(Fucα1-6)GlcNAc. These data indicated that highly sialylated oligosaccharides increased in peripheral nerve glycoproteins of aged rats. [J Physiol Sci. 2006;56 Suppl:S214]
