Isolation and identification of poly-alpha-(1-->4)-linked 3-O-methyl-D-mannopyranose from a hot-water extract of Mycobacterium vaccae.
A polysaccharide around 3.6 kDa has been identified as the major carbohydrate moiety of a antineoplastic protein-polysaccharide complex (PS4A) obtained by boiling intact cells of Mycobacterium vaccae in water. 1H and 13C NMR spectra of this polysaccharide suggested it was a highly homogeneous polymer composed substantially of one monomer, probably an alpha-linked O-methylated mannose. Comparison of the COSY spectra of the original and acetylated polymer indicated that the glycosidic linkage and the methyl ether were interchangeable, at O-3 and O-4. Further study demonstrated that the benzyolated hydrolysate of the polymer was 1,2,4,6-tetra-O-benzoyl-3-O-methyl-beta-mannopyranose. The hydrolysate was 3-O-methyl-alpha, beta-mannopyranose and the polymer was therefore poly-alpha-(1-->4)-linked 3-O-methyl-D-mannopyranose. This conclusion was further confirmed with an authentic sample of the monomer, which had spectral data identical to those of the hydrolyzate and co-eluted from an ion-exchange HPLC with the major sugar in the hydrolysate.
Tian
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Institute for Tuberculosis Research, University of Illinois at Chicago 60612, USA.
Li
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A
Farrugia
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IV
Mo
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Crich
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D
Groves
M J
MJ
D000276:Adjuvants, Immunologic / Q000737:chemistry; D002236:Carbohydrate Conformation; D002851:Chromatography, High Pressure Liquid; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000737:chemistry*; D008745:Methylation; D009161:Mycobacterium / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry*
D000276:Adjuvants, Immunologic; D008351:Mannans; D011135:Polysaccharides, Bacterial; C097323:polymannose