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Identification of methylphosphomannosyl residues as components of the high mannose oligosaccharides of Dictyostelium discoideum glycoproteins.
Identification of methylphosphomannosyl residues as components of the high mannose oligosaccharides of Dictyostelium discoideum glycoproteins.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 1984 Nov 25; Vol. 259 (22), pp. 13762-9. - Publication Year :
- 1984
-
Abstract
- Lysosomal enzymes isolated from the slime mold Dictyostelium discoideum bind to the mannose 6-phosphate receptor which is present in many mammalian cells. While binding to the receptor suggests that the slime mold enzymes possess the same mannose 6-phosphate recognition marker as their mammalian counterparts, initial structural studies of the phosphorylated oligosaccharides have indicated that the phosphate is attached to high mannose-type units via an unusual phosphodiester linkage (Freeze, H.H., Yeh, R., Miller, A.L., and Kornfeld, S. (1983) J. Biol. Chem. 258, 14874-14879). To identify the components of the phosphodiester group we have isolated the phosphorylated high-mannose oligosaccharides from D. discoideum AX3 cells labeled with [2-3H]mannose or [6-3H]glucosamine and from the differentiation medium of unlabeled cells. The major phosphorylated species contain one or two phosphodiester groups and an average of 6 or 7 mannose residues. The phosphodiesters are relatively stable to both acid and base hydrolysis, but upon strong acid hydrolysis (conditions that completely hydrolyze the oligosaccharide) mannose 6-phosphate residues are liberated. Through a combination of techniques, including fast atom bombardment and direct chemical ionization mass spectrometry, it is shown that the mannose 6-phosphate residues of the intact oligosaccharide are diesterified to methyl groups. This indicates that slime mold possesses a different biosynthetic pathway for the formation of phosphorylated high mannose-type oligosaccharides than is utilized by higher organisms.
- Subjects :
- Chromatography, High Pressure Liquid
Chromatography, Ion Exchange
Chromatography, Paper
Magnetic Resonance Spectroscopy
Mass Spectrometry
Dictyostelium analysis
Hexosephosphates analysis
Mannosephosphates analysis
Methylglycosides analysis
Methylmannosides analysis
Oligosaccharides analysis
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 259
- Issue :
- 22
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 6501278