The structure and mechanism of action of cellulolytic enzymes.

The modern structural classification of polysaccharases comprising cellulase-hemicellulase enzyme systems is discussed. Their catalytic domains are currently grouped into 15 of more than 80 known glycosyl hydrolase families, whereas substrate binding domains fall into 13 families. The structures of catalytic and substrate binding domains, as well as linker sequences, are briefly considered. A hypothetical mechanism of concerted action of catalytic and substrate binding domains of cellobiohydrolases on the surface of highly ordered cellulose is suggested.