Struktur der Zellwandpolysaccharide in der Futtereiweiß-Hefe Candida spec. H. I. Struktur des alkalistabilen Mannan-Proteins

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 branchpoints. The research of the acetolysis fragments revealed that the molecule is composed of mannose and mannooligosaccharides with DP2 to DP12. These oligosaccharides are terminated in the nonreducing end by α(1,2)- and α(1,3)-linked mannose residues. The pentasaccharide is terminated only by an α(1,3)-mannose. Glucose was only found in the monosaccharide fraction corresponding to the nonsubstituted backbone and in the α(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-β-D-glucosyl-N-acetyl-D-glucosamine to the asparagine residue of the protein.