PMID: 13917Jan 1, 1977

Kinetics of the hydrolysis of cellobiose and p-nitrophenyl-beta-D-glucoside by cellobiase of Trichoderma viride

Canadian Journal of Biochemistry
R J Maguire

Abstract

Cellobiase has been isolated from the crude cellulase mixture of enzymes of Trichoderma viride using column chromatographic and ion-exchange methods. The steady-state kinetics of the hydrolysis of cellobiose have been investigated as a function of cellobiose and glucose concentrations, pH of the solution, temperature, and dielectric constant, using isopropanol-buffer mixtures. The results show that (i) there is a marked activation of the reaction by initial glucose concentrations of 4 X 10(-3) M to 9 X 10(-2) M and strong inhibition of the reaction at higher initial concentrations, (ii) the log rate -pH curve has a maximum at pH 5.2 and enzyme pK values of 3.5 and 6.8, (iii) the energy of activation at pH 5.1 is 10.2 kcal mol-1 over the temperature range 5-56 degrees C, and (iv) the rate decreases from 0 to 20% (v/v) isopropanol. The hydrolysis by cellobiase (EC 3.2.1.21) of p-nitrophenyl-beta-D-glucoside was examined by pre-steady-state methods in which [enzyme]0 greater than [substrate]0, and by steady-state methods as a function of pH and temperature. The results show (i) a value for k2 of 21 S-1 at pH 7.0 (where k2 is the rate constant for the second step in the assumed two-intermediate mechanism (formula: see text), (ii) a...Continue Reading

Citations

Jan 1, 1982·The International Journal of Biochemistry·J G Shewale
Sep 5, 2002·Microbiology and Molecular Biology Reviews : MMBR·Lee R LyndIsak S Pretorius
Mar 1, 1981·Archives of Biochemistry and Biophysics·J G Shewale, J Sadana
Dec 1, 1983·Biotechnology and Bioengineering·J D Ferchak, E K Pye
Jul 20, 1988·Biotechnology and Bioengineering·A AdamiR Craveri
Jun 1, 1985·Biotechnology and Bioengineering·L Kantham, V Jagannathan

Related Concepts

Endoglucanase Y
Hyphomycetes
Disaccharides
Glucosidase
Glucosides
Glycosides
Hydrogen-Ion Concentration
Mathematics
Nitrobenzenes
Trichoderma

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