Isolation of mannan-protein complexes from viable cells of Saccharomyces cerevisiae X2180-1A wild type and Saccharomyces cerevisiae X2180-1 A-5 mutant strains by the action of Zymolyase-60,000

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Abstract
The viable whole cells of S.cerevisiae X2180-1A wild type and its mannan mutant strain S. cerevisiae X21801-A, were treated with an Arthrobacter sp. .beta.-1,3-glucanase in the presence of a serine protease inhibitor, phenylmethylsulfonyl fluoride. Fractionation of the solubilized materials of each strain with Cetavlon (cetyltrimethylammonium bromide) yielded one mannan-protein complex. Molecular weights of these complexes were almost the same as that of the mannoprotein of the mutant strain prepared by Nakajima and Ballou, which had a MW of 133,000 and were approximately 3 times larger than those of the mannans isolated from the same cells by hot-water extraction. Each mannan-protein complex contained up to 2% glucose residue, which was not removed by specific precipitation with anti-mannan sera or by affinity chromatography on a column of concanavalin A-Sepharose. Treatment of these complexes with alkaline NaBH4 produced peptide-free mannan containing small amounts of glucose nearly identical to those of the parent complexes. The above findings provide evidence that the glucose residues exist in a covalently linked form to the mannan moiety. Fractionation of the mannan-protein complex of the S. cerevisae wild-type strain by DEAE-Sephadex chromatography yielded 5 subfractions of different phosphate content, indicating that these highly intact mannan-protein complexes were of heterogeneous material consisting of many molecular species of different phosphate content.