Transglycosylation activities of exo- and endo-type cellulases from Irpex lacteus (Polyporus tulipiferae).
Two highly purified cellulases, Ex-1 [exo-type, exo-cellobiohydrolase, EC 3.2.1.91] and En-1 [endo-type, EC 3.2.1.4] obtained from Driselase, a commercial enzyme preparation from Irpex lacteus (Polyporus tulipiferae), were used in this work. Both cellulases produced 14C-cellooligosaccharides such as 14C-G2 and 14C-G3 by transglycosylation when G3, G5, or beta-PNPC was used as a donor and 14C-G1 as an acceptor. However, the transglycosylation activity of Ex-1 was far higher than that of En-1. When Ex-1 or En-1 was incubated with beta-PNPG only, no p-nitrophenol was released, but it was readily released when G3 was added to the reaction mixture. In this reaction, the optimal donor (G3) concentration for Ex-1 was 1.0 mM, and the optimal pH values of Ex-1 were at 2.7 and 3.7 for beta-PNPG and beta-PG as acceptors, respectively, these values being far lower than the ordinary optimal pH values of the cellulase (4.0-5.0).
D001487:Basidiomycota / Q000201:enzymology*; D002480:Cellulase / Q000378:metabolism*; D044643:Glucan 1,4-beta-Glucosidase; D005947:Glucose / Q000378:metabolism*; D005959:Glucosidases / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009596:Nitrophenols; D011124:Polyporaceae / Q000201:enzymology*; D011134:Polysaccharides / Q000302:isolation & purification; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000378:metabolism*
D009596:Nitrophenols; D011134:Polysaccharides; D005959:Glucosidases; D001617:beta-Glucosidase; D002480:Cellulase; D044643:Glucan 1,4-beta-Glucosidase; D005947:Glucose; C024836:4-nitrophenol