Mechanism of action of malt beta-glucanases: 9. The structure of barley beta- d-glucan and the specificity of A 11-endo-beta-glucanase

Abstract

Several concentrations of periodate were used to oxidize barley beta- d-glucan. Measurement of the periodate consumed and Chromatographic examination of the products indicated that the beta- d-glucan was linked by 70% (1 → 4)-bonds and 30% (1 → 3)-bonds. There were no adjacent (1 → 3)-bonds in the beta- d-glucan. The action of A 11-endo-beta-glucanase, a germinated barley enzyme which hydrolyzes beta- d-glucan, was tested on compounds containing a variety of beta-glucosidic linkages. The enzyme was unable to hydrolyze laminarin, carboxymethyl cellulose, oligosaccharides containing consecutive (1 → 3)-bonds, consecutive (1 → 4)-bonds, 4-0-beta- d-laminaribiosyl- d-glucose, 4-0-beta- d-laminaribiosyl- d-cellobiose, 3-0-beta- d-cellobiosyl- d-glucose, 3-0-beta- d-cellotriosyl- d-glucose, or two other more complex beta-linked glucose oligosaccharides whose structures are not completely established.