THERMODYNAMIC PARAMETERS OF THE REVERSIBLE ISOMERIZATION OF ASPARTIC RESIDUES VIA A SUCCINIMIDE DERIVATIVE

Authors
Citation
S. Capasso, THERMODYNAMIC PARAMETERS OF THE REVERSIBLE ISOMERIZATION OF ASPARTIC RESIDUES VIA A SUCCINIMIDE DERIVATIVE, Thermochimica acta, 286(1), 1996, pp. 41-50
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Analytical
Journal title
ISSN journal
0040-6031
Volume
286
Issue
1
Year of publication
1996
Pages
41 - 50
Database
ISI
SICI code
0040-6031(1996)286:1<41:TPOTRI>2.0.ZU;2-0
Abstract
Values of the thermodynamic quantities Delta H degrees and Delta S deg rees for the reactions ''Asp-peptide reversible arrow Asu-peptide reve rsible arrow beta-Asp-peptide'' in aqueous solution have been obtained for the model peptides Ac-Gly-X-Gly-Gly-NHMe and Ac-X-Gly-NHMe (X = A sp, beta-Asp, Asu; Asu = aminosuccinyl residue) from the temperature-d ependence of equilibrium constants. The Delta H degrees and Delta S de grees values for the cyclization reactions of the carboxylic-acid form of the Asp and beta-Asp side chains of the dipeptides and tetrapeptid es are positive and coincident within experimental error. Medium value s are 34 kJ mol(-1) and 127 J K-1 mol(-1) for Delta H degrees and Delt a S degrees, respectively. The molar enthalpies and molar entropies of the Asp-dipeptide and beta-Asp-dipeptide, and of the Asp-tetrapeptide and beta-Asp-tetrapeptide, did not exhibit significant differences.