Fine substrate specificities of four exo-type cellulases produced by Aspergillus niger, Trichoderma reesei, and Irpex lacteus on (1 linked to 3), (1 linked to 4)-beta-D-glucans and xyloglucan

• Published in: Journal of biochemistry (Tokyo) Vol. 120; no. 6; pp. 1123 - 1129
• Main Authors: Amano, Y, Shiroishi, M, Nisizawa, K, Hoshino, E, Kanda, T
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.12.1996
• Subjects: Aspergillus niger; Aspergillus niger - enzymology; barley glucan; beta-Galactosidase - chemistry; beta-Galactosidase - metabolism; beta-glucans; Cellulase - chemistry; Cellulase - metabolism; cellulases; Cellulose 1,4-beta-Cellobiosidase; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; enzyme activity; exo-cellulase; Fungal Proteins - chemistry; Fungal Proteins - metabolism; fungi; Glucans - metabolism; Glycoside Hydrolases; Hypocrea jecorina; Irpex lacteus; Polysaccharides - metabolism; Structure-Activity Relationship; Substrate Specificity; substrates; Trichoderma - enzymology; Xylans; xyloglucan; xyloglucans
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a021531

To investigate the fine substrate specificities of four highly purified exo-type cellulases (Exo-A from Aspergillus niger, CBHI and CBHII from Trichoderma reesei, and Ex-1 from Irpex lacteus), water-soluble substrates such as barley glucan, xyloglucan from tamarind (Tamarindus indica L.), and their oligosaccharides were employed. Four exo-type cellulases immediately hydrolyzed 3-O-beta-D-cellotriosylglucose to produce cellobiose and laminaribiose. In contrast, CBHII showed no hydrolytic activity towards 3(2)-O-beta-D-cello-biosylcellobiose, which was hydrolyzed to cellobiose by the other exo-type cellulases. These cellulases hydrolyzed the internal linkages of barley glucan and lichenan in an endo-type fashion to produce cellobiose and mix-linked oligosaccharides as main products. The DP-lowering activities of the four exo-type cellulases on barley glucan were in the order of Ex-1, CBHII, Exo-A, and CBHI. Based on gel permeation chromatography analysis of the hydrolysates, Ex-1 seemed to attack the internal cellobiosyl unit adjacent to beta-1,3-glucosidic linkages in barley glucan molecule more frequently than did the other cellulases. Xyloglucan was hydrolyzed only by CBHI and CBHII, and produced hepta-, octa-, and nona-saccharides. In addition, a xyloglucan tetradecasaccharide (XG14) was split only to heptasaccharide (XG7) by CBHI and CBHII.