A Re-evaluation of the Oligosaccharide Sequence Associated with Ovalbumin

作者：Anthony L. Tarentino, Thomas H. Plummer, Frank Maley · 发表于：Journal of Biological Chemistry · 年份：1972 · DOI：10.1016/s0021-9258(19)45472-0 · 被引用次数：65 · 研究领域：Enzyme Production and Characterization、Carbohydrate Chemistry and Synthesis、Infant Nutrition and Health

Abstract A glycosyl asparagine unit, Asn-(GlcNAc)2(Man)1, was isolated from ovalbumin by proteolytic and glycosidase digestion. The terminal disaccharide d-Man (1 → 4)-GlcNAc, released by an endoglycosidase partially purified from chitinase, was shown by optical rotatory dispersion, infrared analysis, and gas chromatography to possess the characteristics of a β-mannosidic linkage. The chemical data thus confirm the enzyme studies which demonstrated the specific cleavage of this bond by a hen oviduct β-mannosidase (Sukeno, T., Tarentino, A. L., Plummer, T. H., Jr., and Maley, F. (1971) Biochem. Biophys. Res. Commun. 45, 219). The endoglycosidase also hydrolyzed the parent ovalbumin glycosyl asparagine unit, Asn-(GlcNAc)4(Man)6, to Asn-GlcNAc and the oligosaccharide (Man)6(GlcNAc)3. Smith degradation verified the presence of N-acetyl-d-glucosamine on the reducing end of the oligosaccharide with the mannosyl units linked to C4, or C3 and C4. These results suggest, in contrast to previous findings, that the polymannosyl unit of the ovalbumin oligosaccharide is associated with the distal and not the proximal end of di-N-acetylchitobiose.