β-D-GLUCOSIDASES OF SCLEROTIUM ROLFSII. SUBSTRATE SPECIFICITY AND MODE OF ACTION

DOI: 10.1016/0008-6215(83)88048-3

Source and publish data:

Carbohydrate Research p. 205 - 214 (1983)

Update date:2022-08-12

Topics:

Authors:

Sadana, Jai C.

Shewale, Jaiprakash G.

Patil, Rajukmar V.

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Article abstract of DOI:10.1016/0008-6215(83)88048-3

The substrate specificity and mode of action of the four pure β-D-glucosidase enzymes (EC 3.2.1.21) from Sclerotium rolfsii were studied and their contribution to cellulolysis is discussed.The enzymes are specific for substrates having the β-D-configuration.The specificity of the enzymes is not restricted to the β-D-(1<*>4) linkage, as all four β-D-glucosidases hydrolized substrates having β-D-(1<*>6)-,-(1<*>3) and -(1<*>2) linkages.The enzymes require strictly a D-gluco configuration for activity.The β-D-glucosidases had no action on highly ordered cellulose, such as Avicel, but slowly hydrolized disordered cellulose (phosphoric acid-swollen Avicel) and carboxymethylcellulose, and rapidly cellodextrins, removing D-glucose residues from the nonreducing end.The pure enzymes behaved rather as exo-β-D-glucan glucohydrolase.The K_m values of all four β-D-glucosidases decreased with increase in the chain length of cellodextrins.Cellopentaose was the preferred substrate for all four enzymes.The major route of D-glucose formation from cellulose by hydrolysis with S.rolfsii β-D-glucosidases proceeds through higher-molecular weight cellodextrins.