  The statistical properties of protein folding within the {\phi}^4 model are
investigated. The calculation is performed using statistical mechanics and path
integral method. In particular, the evolution of heat capacity in term of
temperature is given for various levels of the nonlinearity of source and the
strength of interaction between protein backbone and nonlinear source. It is
found that the nonlinear source contributes constructively to the specific heat
especially at higher temperature when it is weakly interacting with the protein
backbone. This indicates increasing energy absorption as the intensity of
nonlinear sources are getting greater. The simulation of protein folding
dynamics within the model is also refined.
