Beta-glucosidase Kinetics

Unlike the major cellulase components, beta-glucosidase is a soluble enzyme acting on a soluble substrate. Beta-glucosidase is characterized by classical Michaelis-Menten kinetics, with glucose acting as a competitive inhibitor [32]  

Values of the kinetic constants for beta-glucosidase from Trichoderma and Aspergillus are shown in Table 2. 

Beta-glucosidase is available within the complex mixture of crude cellulase enzymes. In addition, some microbes, including Aspergillus niger, produce beta-glucosidase with httle additional cellulase activity. 

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Kempton JB, Withers SG (1992) Mechanism of Agrobacterium beta-glucosidase Kinetic studies. Biochemistry 31 9961-9969... 

Dignum M, van der Heijden R, Kerler J, Winkel C, Verpoorte R (2004) Identification of glu-cosides in green beans of Vanilla planifolia Andrews and kinetics of vanilla beta-glucosidase. Food Chem 85 199-205... 

When faced with characterizing the kinetic behavior of an enzyme or a complex of enzymes, one usually pulls out a textbook on Michaelis-Menten kinetics and applies it to the system at hand. For beta-glucosidase, which hydrolyzes the soluble substrate cellobiose to glucose, this approach is fine. Unfortunately, for cellulase enzymes producing cellobiose from cellulose, this exercise is inadequate. 

Adney, W. S., Baker, J. O., Vinzant, T. B., Thomas, S. R., and Himmel, M. E., Kinetic comparison of beta-D-glucosidases of industrial Importance. Abstracts of Papers of the American Chemical Society 1995, 209, 119-BTEC. 

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