Abstract
To study the structure of yeast (Saccharomyces cerevisiae) mannan, two kinds of the mannan degrading enzymes have been isolated from soil bacteria. An αl, 2-n-mannosidase that hydrolyses specifically αl, 2-linked mannosyl side chains; it has a molecular weight of 380, 000 and is composed of two identical 190, 000 subunits. An endo-al, 6-D-mannanase that hydrolyses al, 6-linked mannan back bone and it consists of a single polypeptide chain with a molecular weight of 131, 000. S. cerevisiae cell wall mannoprotein was selectively hydrolyzed by the al, 6-D-mannanase and an endo-β-N-acetylglucosaminidase to produce the linkage region between protein and polysaccharide parts. The structure of the linkage region was studies by conventional methods including NMR, methylation analysis, acetolysis, and sequential digestion of α- or β-mannosidases. The structures of the residual polysaccharide part and α-linked mannooligosaccharides were also characterized.
