Open AccessThe Mechanism of Enzymatic Cellulose Degradation
Author(s) -
Berghem Lars E. R.,
Pettersson L. Göran
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb02952.x
Subject(s) - chromatography , chemistry , isoelectric point , isoelectric focusing , cellulase , cellobiose , size exclusion chromatography , gel permeation chromatography , sephadex , column chromatography , enzyme , polyacrylamide gel electrophoresis , enzyme assay , biochemistry , organic chemistry , polymer
1 A cellulolytic enzyme (“C 1 ” enzyme) has been isolated from a commercial cellulase preparation derived from culture filtrates of the fungus Trichoderma viride . 2 The purification method is a four‐step procedure including chromatography on Bio‐Gel P‐10, DEAE‐Sephadex chromatography, isoelectric focusing and chromatography on Bio‐Gel P‐60. 3 A yield of 144 mg enzyme was obtained per 100 g commercial cellulase. 4 The isolated enzyme was homogeneous in polyacrylamide gel electrophoresis at pH 5.0 and at pH 8.0 by isoelectric focusing in a polyacrylamide gel and also in the ultracentrifuge. 5 No enzyme activity towards carboxymethylcellulose could be detected in the purified material under the assay conditions used. Similarly, there was no β‐glucosidase activity. 6 The purified enzyme was associated with 3.3% carbohydrate and is assumed to be a glycoprotein. The enzyme was isoelectric at pH 3.79 (10°C). A molecular weight of 46000 was determined by chromatography of the reduced and alkylated enzyme on a calibrated column of Sepharose 6B in 6 M guanidine‐HCl. 7 Crystalline cellulose (Avicel), phosphoric acid‐swollen Avicel and cellotetraose were degraded by the enzyme and in each case the principle reaction product was cellobiose. 8 Evidence indicates that the purified enzyme is a β‐1,4‐glucan cellobiohydrolase.