Modeling adsorption and threading of cellobiohydrolase Cel7A
Thursday, May 1, 2014: 8:25 AM
Grand Ballroom F-G, lobby level (Hilton Clearwater Beach)
Peter Westh1, Nicolaj Bagger1, Nina Lei1, Francieli Colussi1, Trine H. Sorensen1, Johan P. Olsen1, Jeppe Kari1, Kadri Alasepp1, Michael S. Windahl1, Kim Borch2 and Vanessa de Oliveira Arnoldi Pellegrini3, (1)Nsm, Roskilde University, Roskilde, Denmark, (2)Novozymes, Bagsvaerd, Denmark, (3)Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
Enzymatic breakdown of cellulose is an example of heterogeneous catalysis. It follows that a molecular understanding relies on a realistic description of the association of the diffusing species (the enzyme) and the solid sorbent (the substrate). We have studied the thermodynamics and kinetics of this process experimentally and modeled the results to gain insight into different steps of the association process. We found that adsorption of the cellobiohydrolase Cel7A was essentially reversible and also identified possible origins of earlier claims of the opposite. Based on this, we introduced a kinetic model and used this to deconvolute experimental data. Specifically we investigated the kinetic order of the association process with respect to both enzyme and substrate, and derived separate rate constants for the initial adsorption and the subsequent “threading” of the cellulose strand into the active tunnel.