CELLULASE, is a class of enzymes that attack cellulose the principal material of land plant cell walls. Cellulase degrades cellulose to short fragments with 6 to 10 or so glucose residues. These are then degraded to glucose by the enzyme cellobiase, which invariably accompanies cellulase but is not able to attack high-molecular-weight cellulose.
Cellulases occur in organisms that use cellulose as a source of carbon in their nutrition. Examples include wood-rotting fungi, certain bacteria, and protozoa that live symbiotically in the rumen of the cow and in the guts of snails, ship-worms, and many insects.
Two cellulases with molecular weights of 11,400 and 51,000 have been prepared in pure form from the fungus Polyporus versicolor.