Six endoglucanases (Endo I; 11; 111; IV; V; VI), three exoglucanases (Ex0 I; 11; 111) and a P-glucosidase (P-gluc I) were isolated from a commercial cellulase preparation derived from Trichoderma viride, using gel filtration on Bio-Gel, anion exchange on DEAE-Bio-Gel A, cation exchange on SE-Sephadex and affinity chromatography on crystalline cellulose. Molecular masses were determined by polyacrylamide gel electrophoresis. One group of endoglucanases (Endo I, Endo I1 and Endo IV) with M , of 50000, 45000 and 23500 were more random in their attack on carboxymethylcellulose than another group (Endo 111, Endo V and Endo VI) showing M , of 58000, 57000 and 53000 respectively. Endo 111 was identified as a new type of endoglucanase with relatively high activity on crystalline cellulose and moderate activity on carboxymethylcellulose. Exo I1 and Exo 111 with M, of 60500 and 62000 respectively showed distinct adsorption affinities on a column of crystalline cellulose and could be eluted by a pH gradient to alkaline regions. These enzymes were cellobiohydrolases as judged by highpressure liquid chromatography of the products obtained from incubation with H3P04-swollen cellulose. It was concluded that these exoglucanases are primarily active on newly generated chain ends. Exo I was essentially another type of exoglucanase which in the first instance was able to split off a cellobiose molecule from a chain end and then hydrolyse this molecule in a second step to two glucose units. P-Gluc I was a new type of aryl-P-Dglucosidase which had no activity on cellobiose. The enzyme had a M , of 76000 and was moderately active on CM-cellulose, crystalline cellulose and xylan and highly active on p-nitrophenyl-8-D-glucose and p-nitrophenyl-P-D-xylose.Much attention is paid to the enzymatic hydrolysis of cellulose because it is a renewable carbon source and available in large quantities. Cellulases from fungal origin are known to be most powerful in cellulose hydrolysis. Cellulase preparations are derived, among other, from Trichoderma reesei [l, 21, Trichoderma viride [3], Trichoderma koningii [4] and Sporotrichum pulverulentum [5]. These microorganisms produce a multi-component enzyme system, including the 1,4-p-D-glucan glucanohydrolase (endoglucanase; EC 3.2.1.4), 1,4-P-D-glucan cellobiohydrolase (exoglucanase; EC 3.2.1.91) and p-D-glucoside glucohydrolase (P-glucosidase; EC 3.2.1.21). A combination of these three types of enzymes is necessary for the complete hydrolysis of crystalline cellulose. Endoglucanase and exoglucanase are known to act synergistically in cellulose hydrolysis [6], while P-glucosidase is needed for removal of cellobiose, a strong inhibitor of both endoglucanase and exoglucanase [7]. However, the debate on the mechanism of cellulose hydrolysis still continues. The diversity of endoglucanases, exoglucanases and P-glucosidases from fungal origin is emphasized by many review reports on this subject [7 -131. Comparative studies are difficult and sometimes confusing since several species with different strains...
