title: Purification and properties of an exo-cellulase of Avicelase type from a wood-rotting fungus, Irpex lacteus (Polyporus tulipiferae).
abstract: A cellulase component of Avicelase type was obtained from Driselase, a commercial enzyme preparation from a wood-rotting fungus Irpex lacteus (Polyporus tulipiferae). It showed a single band on SDS-polyacrylamide electrophoresis. The amino acid composition of this cellulase resembled those of cellulase components of endo-type from the same fungus. However, it produced exclusively cellobiose from CMC as well as from water-insoluble celluloses such as Avicel or cotton at earlier stages of hydrolysis. In addition, the hydrolysis of CMC practically stopped after an initial rapid stage. The cellulase showed a strong synergistic action with an endo-cellulase of higher randomness (typical CMCase-type) in the hydrolysis of CMC as well as Avicel. In contrast to cellotriose and -tetraose, cellopentaose and -hexaose were attacked very rapidly, and only cellobiose was produced. These results suggest that the cellulase is an exo-type component. However, it mutarotated the products from cellopentaitol in the same direction as endo-cellulases. it represented a relatively large portion of the total cellulase activity, and may play an important role in the degradation of native cellulose in vivo.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001487:Basidiomycota / Q000201:enzymology*; D002266:Carboxymethylcellulose Sodium / Q000378:metabolism; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D011124:Polyporaceae / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D000596:Amino Acids; D002482:Cellulose; D002480:Cellulase; D002266:Carboxymethylcellulose Sodium