2Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142292 Russia; fax: (095) 923-3602; E-mail: okunev@ibpm.serpukhov.su
* To whom correspondence should be addressed.
Received January 25, 1999; Revision received March 10, 1999
Four major components of the cellulase complex of Chaetomium cellulolyticum have been isolated by gel-filtration, ion-exchange chromatography on DEAE-Toyopearl and Macro Prep Q, and chromatofocusing on Mono P. These components include three endoglucanases (19, 35, and 40 kD) and a cellobiohydrolase (45 kD). The isoelectric points of the enzymes vary from 3.8 to 4.2. The optimal pH values for catalytic activity are in the range 4.5-6.0, and the optimal temperatures are in the range 60-70°C. Of these enzymes the 19 kD endoglucanase is the most stable; it retained high activity within a broad pH range (from 5.0 to 9.6) at 50°C for 3 h. This enzyme also had the highest topolytic activity determined by the efficiency of removal of indigo from the surface of cotton.
KEY WORDS: cellulase, endoglucanase, cellobiohydrolase, purification, biological bleaching