THE STRUCTURE OF LICHENIN: SELECTIVE ENZYMOLYSIS STUDIES

• Published in: Canadian Journal of Chemistry
• Main Authors: Perlin, A. S., Suzuki, S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1962
• Subjects: Iceland
• Online Access: http://dx.doi.org/10.1139/v62-009; http://www.nrcresearchpress.com/doi/pdf/10.1139/v62-009

Lichenin, the poly-β-D-glucan of Cetraria islandica (Iceland moss), is found by enzymic degradation to differ in fine structure from the poly-β-D-glucans of cereal grains. Enzymolysis has been carried out with a cellulase and a laminarinase preparation, the former yielding mainly O-β-D-glucopyranosyl-(1 → 3)-O-β-D-glucopyranosyl-(1 → 4)-α-D-glucose, and the latter mainly O-β-D-glucopyranosyl-(1 → 4)-O-β-D-glucopyranosyl-(1 → 3)-α-D-glucose. Di-and tetra-saccharides are produced in small proportions. Steric aspects of these enzymic degradations are discussed. The basis constitution of lichenin is represented by a tetrameric unit in which two adjacent (1 → 4) linkages alternate with an isolated (1 → 3) linkage; occasionally four consecutive monomers are linked by (1 → 4) bonds. The glucans of cereal origin differ mainly in possessing a higher proportion of the latter structural sequence. Despite their close chemical similarity to cellulose, all of these glucans are soluble, a property that appears to be related to the even distribution of β-(1 → 3) bonds along the chains, with a resulting disruption of linear orientation effects.