Abstract
We investigated the structural changes in asparagine-linked sugar chains of rat sciatic nerve glycoproteins during aging. High-mannose-type sugar chains were abundant in younger animals, whereas sialylated sugar chains were increased by aging. We previously reported that two sialylated/sulfated oligosaccharides, OIBA1 and OIBA2, increased during maturation. The molecular weights (Mw) of de-sialylated OIBA1 and de-sialylated OIBA2 were the same and so were their retention times on HPLC, indicating that the core structures of OIBA1 and OIBA2 are the same. The common structure of both the OIBA1 and the OIBA2 was determined to be a bi-antennary complex-type oligosaccharide; Galβ1-4GlcNAcβ1-2-Manα1-6(Galβ1-4GlcNAcβ1-2Manα1-3)Manβ1-4GlcNAc. Sulfate residue linked to the 6-O-GlcNAc on the C3 antenna. Non-sialylated form of OIBAs was also found in the oligosaccharides from nerve tissues. Neuraminidase digestion experiments indicated that OIBA2 is di-sialylated in tandem at the non-reducing terminal of the C6 antenna. Neuraminidases digestion experiments and time-of-flight (TOF) mass spectrometric analyses reveled that there were many complex-type oligosaccharides containing di/oligo sialylic acids in aged rats. [Jpn J Physiol 55 Suppl:S205 (2005)]
