Differential Scanning Calorimetry (DSC) study of calf thymus DNA was carried out measure the midpoint of thermal denaturation (Tm), Hm (enthalphy change at Tm) and Cp (constant-pressure heat capacity change). It has been observed that Cp=0. Tm=755 C and Hm=50.4 K cal/mole. The Gibbs free energy change at 37 C is then-