In this paper it is pointed out that there is a convergence temperatur
e for the enthalpy change associated with the dissolution process into
water of four solid cz-amino acids: glycine, DL-alpha-alanine, DL-alp
ha-aminobutyric acid and DL-alpha-norvaline. It is important that the
value of the convergence temperature for alpha-amino acids, T-H = 91.
2 +/- 6.3 degrees C is very close to that determined for the denaturat
ion of small globular proteins, T-H = 100 +/- 6 degrees C. This resul
t is analysed thoroughly in order to obtain information about the ener
getics of the protein denaturation process. The analysis points out th
at there is an energy penalty, due to the dehydration and burial of po
lar groups, that tends to counterbalance the energy gain due to the fo
rmation of polar and dispersive interactions in the close-packed inter
ior of globular proteins.