Abstract
The biosynthesis of the β-glucan and the chitin-like substance, main components of the cell wall of Cochliobolus miyabeanus, were studied. The chemical structures of the synthesized polysaccharides by incubating with mycelial enzyme (soluble enzyme, particulate enzyme, crude enzyme), UDP-14C-glucose or UDP-14C-N-acetylglucosamine and glucan or chitodextrin were examined. Judging from these results, possible synthetic pathways were presented. N-acetylglucosaminyl residues were transfered to the non reducing terminals of chitodextrin from UDP-sugar molecules by incubating with the particulate enzyme, forming a straight chain of β-1, 4 linked N-acetylglucosamine polymer. A part of the UDP-N-acetylglucosamine was converted to UDP-N-acetylgalactosamine with the soluble enzyme, followed by forming branched unit of N-acetylgalactosamine connected through C-1 by α-glycosidic linkage with the particulate enzyme. In the glucan synthesis glucosyl residued were transfered to the non reducing terminal and the internal glucosyl residues of β-glucan from UDP-glucose molecules by the particulate enzyme, forming the β-1, 3 glucan having branched units connected through C-6 and C-1.
