Synergistic interactions in cellulose hydrolysis

Cellulases acting on crystalline cellulose in synergistic mixtures have higher combined activities than the sum of their individual activities. The mechanisms by which different types of cellulases enhance each other's activities are complex and not completely understood, and the published data is often inconsistent. We discuss the role of the substrate and experimental factors in synergism experiments and consider the various modes of synergism that have been proposed. New oxidoreductase enzymes that participate in novel synergistic reactions are also discussed. Finally, we propose a general encompassing synergism model, based on the observations described in the review.