CONSTITUTION OF A GLUCOMANNAN FROM THE SAPWOOD OF SUGAR MAPLE (ACER SACCHARUM)

Abstract

A glucomannan containing D-mannose and D-glucose in a molar ratio of 7:3 has been isolated from sugar maple sapwood. Electrophorectic examination in acetate and borate buffers showed that the polysaccharide was essentially homogeneous. Methylation and hydrolysis of the glucomannan yielded the following O-methyl ethers:2,3,4,6-tetra-O-methyl-D-glucose (1.1%),2,3,4,6-tetra-O-methyl-D-mannose (2.3%),2,3,6-tri-O-methyl-D-glucose (23.4%),2,3,6-tri-O-methyl-D-mannose (65.9%),2,3-di-O-methyl-D-glucose (2.6%),2,3-di-O-methyl-D-mannose (2.7%).These data in conjunction with periodate oxidation results and estimates of the degree of polymerization indicated that the glucomannan was composed of 25–27 hexose units linked β(1 → 4) in a linear structure. The chains were terminated predominately by D-mannose units; traces of D-xylose were present in terminal positions only and appeared to be part of the glucomannan molecule.