Detection of Man5GlcNAc and related free oligomannosides in the cytosol fraction of hen oviduct

• Published in: Journal of biochemistry (Tokyo) Vol. 125; no. 1; pp. 70 - 74
• Main Authors: Iwai, K, Mega, T, Hase, S
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 1999
• Subjects: alpha-Mannosidase; Animals; Carbohydrate Sequence; chemical composition; chemical structure; Chickens; cytosol; Cytosol - chemistry; Female; free oligosaccharides; hen oviduct; hens; Isomerism; mannose; Mannosidases - metabolism; Mannosides - analysis; Mannosides - chemistry; Mannosides - metabolism; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase - metabolism; Molecular Sequence Data; N-acetylglucosamine; oligomannoside; oligosaccharides; Oligosaccharides - analysis; Oligosaccharides - chemistry; Oligosaccharides - metabolism; oviducts; Oviducts - chemistry; Oviducts - cytology; Subcellular Fractions
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a022270

The presence of free oligomannosides in cytosol has been demonstrated by metabolic radiolabeling, and Manαl-2Manαl-2Manαl-3(Manαl6)Man)β1-4GlcNAc was detected as the main free oligomannoside in Chinese hamster ovary cells [Kmiécik, D., Herman, V., Stroop, C.J.M., Michalski, J.C., Mir, A.M., Labiau, O., Verbert, A., and Cacan, R. (1995) Glycobiology, 5, 483–494]. In the present paper, the isomeric structures and amounts of oligomannosides in the cytosol fraction of hen oviduct were analyzed by pyridylamination and exoglycosidase digestion. Hen oviduct was used since our group has already characterized the cytosolic neutral α-mannosidase and endo-β-N-acetylglucosaminidase obtained from the same source. The amounts of Man2GlcNAc, Man3GlcNAc, Man4GlcNAc, and Man5 GlcNAc were 0.6, 0.6, 0.5, and 0.8nmol/g tissue, respectively, but Man6GlcNAc-Man9 GlcNAc were not detected. The isomeric structures of the Man3GlcNAc-Man5GlcNAc found were (Manαl-2)0-2Manαl–3(Manαl–6)Manβl–4GlcNAc, which were compatible with the substrate specificities of cytosolic endo-β-N-acetylglucosaminidase and neutral α-mannosidase, indicating that these enzymes participate in the formation of the oligomannosides present in the cytosol.