Monday, April 19, 2010
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Assessment of the importance of cellulase sub-site specificity on rate of enzymatic cellulose hydrolysis

Jerome Fox, Seth E. Levine, Douglas S. Clark, and Harvey W. Blanch. Chemical Engineering, University of California, Berkeley, Calvin Hall Rm 250, University of California, Berkeley, CA, 94720, Berkeley, CA 94720

The kinetic impact of cellulase sub-site specificity on enzymatic cellulose hydrolysis rates has been investigated through the integration of experimentally measured adsorption parameters into a mechanistic kinetic model.  Isothermal titration calorimetry and fluorescence-based binding measurements are used to generate adsorption isotherms that can be used to capture enzyme-substrate interactions within the model.  The influence of the catalytic domain on binding behavior is elucidated, and a sensitivity analysis is used to assess the extent to which adsorption phenomena can be rate-limiting.  Surface heterogeneity is seen to significantly influence the predicted kinetics by altering the efficiency of cellulase-cellulose interactions between raw and pretreated lignocellulosic samples.