Structural Examination of Water-soluble Glycans from Fruit Body of Lyophyllum ulmarium No.1

Studies on Constituent of Edible Fungi Part III

Abstract

Structure of one of the water-soluble glycans from fruit body of Lyophyllum ulmarium was studied. An ethanol precipitate from a hot-water extracted fraction of the fruit body was treated with pronase and by the SEVAG method to remove protein. Then, polysaccharides, P-1, P-2 and P-3 were obtained by column chromatography using Sephacryl S-400 gel, and the structure of P-1 was examined. Homogeneity of each compound was confirmed by gel filtration, ultracentrifugal sedimentation analysis and electrophoresis. Molecular weight of P-1 was about 470000. A β-bond dominant structure was elucidated from the facts that [a]²⁰_Dwas+1.30 (C=1, water) and its infrared absorption spectrum. P-1 was composed of mannose, galactose and glucose in molar ratio of 1.0:1.9:5.1. To examine detailed bonding style, periodate oxidation, SMITH degradation and methylation analysis were conducted. Periodate consumption was 1.25mol and 0.56mol of formic acid was produced. Glycerol and non-oxidated glucitol were detected by SMITH degradation and their molar ratio was 1.8: 1.0. From the result of GLC and GLC-MS of the methylated sample, P-1 was estimated to possess a highly branched structure with 1-linked-D-glucopyranosyl+1-linked-D-manno-pyranosyl or one of these, 1, 3-linked-D -glucopyranosyl, 1, 6-linked-n-glucopyranosyl, 1, 6-linked-D-galactopyranosyl, 1, 3, 6-linked-D -glucbpyranosyl, 1, 2, 6-linked-D-galactopyra-nosyl residues. Partial hydrolysis with trifluoroacetic acid suggested that mannose, galactose and glucose were present at or near branch terminals, and the core of the molecule consisted mainly of glucose.