Breakdown of cellulose derivatives by cellulolytic enzymes. I. Action of fungal ß-glucosidases toward substituted PNP ß-D-glucopyranosides
T Nishimura, I Momohara, M Ishihara
The action of fungal ß-glucosidases on the methyl derivatives of p-nitrophenyl (PNP) ß-D-glucopyranoside, which were regioselectively substituted at 0-2, 0-3, 0-4 and 0-6 positions was studied. Several ß-glucosidases from brown-rot, white-rot, and soft-rot fungi and almond were used for the study. These ß-glucosidases did not act on the 2, 3, and 4-0-methyl derivatives, while the 6-0-methyl one was hydrolyzed by all the enzymes to some extent. The results indicate that the methyl group at 0-2, 0-3, 0-4 of the glucopyranoside strongly inhibits the recognition by the ß-glucosidases, while the enzymes do not discriminate the structure difference between PNP ß-glucopyranoside and its methyl derivative at 0-6.