THE ENTHALPY-CONVERGENCE TEMPERATURE FOR THE DISSOLUTION INTO WATER OF SOLID ALPHA-AMINO-ACIDS

Citation
G. Graziano et al., THE ENTHALPY-CONVERGENCE TEMPERATURE FOR THE DISSOLUTION INTO WATER OF SOLID ALPHA-AMINO-ACIDS, Thermochimica acta, 273, 1996, pp. 43-52
Citations number
54
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Analytical
Journal title
ISSN journal
0040-6031
Volume
273
Year of publication
1996
Pages
43 - 52
Database
ISI
SICI code
0040-6031(1996)273:<43:TETFTD>2.0.ZU;2-1
Abstract
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.