1.A low-molecular-weight and a high-molecular-weight 1,4-P-glucan glucanohydrolase (C, enzyme) have been isolated from a commercial cellulase preparation derived from culture filtrates of the fungus Trichoderma viride.2. The purification method for the isolation of the low-molecular-weight enzyme is a three-step procedure including chromatography on Bio-Gel P-10, chromatography on a dipolar adsorbent (arginine-Sepharose 6 B) and isoelectric focusing.3. The starting material for the isolation of the high-molecular-weight enzyme was pre-fractionated by chromatography on Bio-Gel P-1 0, by DEAE-Sephadex chromatography and by SE-Sephadex chromatography as described previously by us. Further fractionation of this material was achieved by affinity chromatography and repeated isoelectric focusing. 4.Free zone electrophoresis of the low-molecular-weight enzyme indicated a homogeneous protein. The high-molecular-weight enzyme was homogeneous in sedimentation equilibrium analysis.5. The molecular weights of the enzymes were 12500 and 50000 f 2000 respectively. The former value was determined by chromatography on a calibrated column of Bio-Gel P-100 and the latter value by sedimentation equilibrium analysis.6. The low-molecular-weight enzyme was isoelectric at pH 4.60 (10 "C) and contained 21 % carbohydrate. The corresponding values for the high-molecular-weight enzyme were pH 3.39 and 12 %.7. Both enzymes were active in releasing free fibers from filter-paper. The low-molecular-weight enzyme was estimated to be about twice as effective as the high-molecular-weight enzyme in this regard.Cellulolytic enzymes of endo-1 ,CP-glucanase type have been isolated from culture filtrates of several cellulolytic fungi [l -91. These enzymes attack soluble cellulose derivatives, e.g. sodium carboxymethylcellulose and swollen cellulose, while the effect on native cellulose is still uncertain [l]. The proposed role of the endoglucanase in the over-all process of enzymic cellulose degradation is that they split the cellulose chains in less ordered regions of the cellulose fibre thus creating starting points for attack by exoglucanases [ l l -131. However, the exact role of the endoAbbreviation. CM-cellulase, activity towards carboxymethylcellulose.Enzymes. C,, 1,4-P-glucan glucanohydrolase or endoglucanase (EC 3.2.1.4); /?-glucosidase or cellobiase (EC 3.2.1.21); C,, 1,4-8-glucan cellobiohydrolase or exoglucanase (EC 3.2.1.74).-~ glucanases in the degradation process has not yet been fully understood.Both high-molecular-weight and low-molecularweight endoglucanases have been reported from several fungi [9,14,15]. The low-molecular-weight endoglucanase from Trichoderma viride was considered as 'non-essential' by Selby and Maitland in the total process of enzymic cellulose degradation [5]. Halliwell and Riaz, however, have shown that the low-molecular-weight endoglucanase from Trichoderma koningii promotes the formation of short fibres from native cellulose substrates [16].The object of the present work has been to isolate a low-molecular-wei...

No abstract