[Cell wall polysaccharide structure in the food protein yeast, Candida spec. H. I. Structure of alkali-stable...

The isolated manno-protein contains about 80% mannose and 10% glucose. Methylation analysis established the highly branched nature of this polysaccharide and the presence of 1,2-, 1,3- and 1,6-linkages, as well as the linkages of the branch points. The research of the acetolysis fragments revealed that the molecule is composed on mannose and mannooligosaccharides with DP2 to DP12. These oligosaccharides are terminated in the nonreducing end by alpha(1,3)-mannose. Glucose was only found in the monosaccharide fraction corresponding to the nonsubstituted backbone and in the alpha(1,3)-disaccharide fraction (reducing and nonreducing end) of the acetolysis. A heptasaccharide fraction corresponding to the N-glycosidical linkage region between polysaccharide and protein parts of the glycoprotein had been isolated. 1H-NMR spectroscopy and chemical characterization made it probable that the unit with the first side chain, mannopentaose, is linked by di-N,N' -acetylchitobiose or by 4-0-beta-D-glucosyl-N-acetyl-D-glucosamine to the asparagine residue of the protein.