Nonlinear vibrations in a 2-dimensional protein cluster model with linear bonds

A two dimensional model for the substrate inside a pocket of an active site of an enzyme is presented and investigated as a vibrational system. The parameters of the system are evaluated for a-chymotrypsin. In the case of internal resonance it is analytically and numerically shown that the energy concentrated on a certain degree of freedom might be several times larger than in the non-resonant case. Additionally, the system is driven by harmonic excitations and again energy due to nonlinear phenomena is redistributed inhomogeneously. These results may be of importance for the determination of the rates of catalytic events of substrates bound in pockets of active sites.