Synergism Between Enzymes Involved in the Solubilization of Native Cellulose

Although it is well established that certain cellulolytic fungi hydrolyze native cellulose with enzyme systems containing endo- and exo-β-1,4-glucanase, and β-glucosidase activities, the actual mechanism by which soluble fragments are removed from the more crystalline areas is as yet unknown. Synergism between endoglucanases (so-called Cx) and certain exoglucanases (so-called C1) is clearly established, and many believe that attack is initiated by the Cx and that the new chain ends generated are then hydrolyzed by C1. However, the discovery that C1 acts synergistically only with certain Cx components suggests that the proposed mechanism is an oversimplification. Possibly the more crystalline areas are effectively solubilized only by the rapid sequential action of those endo- and exoglucanases capable of forming an enzyme-enzyme complex on the surface of the cellulose chains.