Molecular weight, structure and shape of oat (1 → 3), (1 → 4)-β-D-glucan fractions obtained by enzymatic degradation with (1→ 4)-β-D-glucan 4-glucanohydrolase from Trichoderma reesei

• Published in: Carbohydrate polymers 2001-11, Vol.46 (3), p.275-285
• Main Authors: ROUBROEKS, J. P, ANDERSSON, R, MASTROMAURO, D. I, CHRISTENSEN, B. E, AMAN, P
• Format: Article
• Language: English
• Subjects: Applied sciences; Enzyme kinetics; Exact sciences and technology; Grain (agricultural product); Molecular structure; Molecular weight; Natural polymers; Physicochemistry of polymers; Starch and polysaccharides; Viscosity of liquids
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/S0144-8617(00)00329-5

Oat beta -glucan was partially degraded with (1 arrow right 4)- beta -D-glucan 4-glucanohydrolase for different periods of time. Weight average molecular weight and weight average intrinsic viscosity were obtained from SEC-RI-RALLS-Visc and ranged from 2200 to 213,900 g /mol and 7 to 316 ml/g, respectively. The viscosity equation determined [ eta ] sub(w) = 1.06 x10 super(-2) M super(0) sub(w) super(.86) indicated an extended random coil conformation. When the coil was modelled as a worm-like chain a persistent length of 3.65 nm was obtained. The hydrolysis products identified after extensive degradation were glucose, cellobiose, laminaribiose, 4-O- beta -laminaribiosyl D-glucose, 4-O- beta -laminaribiosyl D-cellobiose and 3-O- beta -cellobiosyl D-cellobiose showing that other enzyme activities were present. The depolymerization kinetics suggested that longer sequences of consecutive (1 arrow right 4)-linkages represent fast hydrolysable sites and the presence of higher relative proportions of (1 arrow right 3)-linkages restricts the affinity of the enzyme. copyright 2001 Elsevier Science Ltd. All rights reserved.