This paper presents a thermodynamic study of DNA through a Peyrard-Bishop one-dimensional lattice with an on-site hump potential. The transfer integral operator method was used to obtain the thermodynamic properties of the system and the solution of the Schrodinger-type equation that emerges from this formalism was determined by the variational method. With the parameters of the potential, commonly used in literature, the value obtained for the denaturation temperature was extremely high. This work suggests different parameters to describe the thermodynamics of DNA macromolecule.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)