Thermodynamic properties of peptide solutions. The relative partial molar enthalpies of aqueous solutions of glycylglycylglycine, glycylglycylalanine and alanylglycylglycine

Abstract

The enthalpies of dilution at 298 K of aqueous solutions of the tripeptides glycylglycylglycine, glycylglycylalanine and alanylglycylglycine have been determined by flow microcalorimetry. From these data the partial molar enthalpies of the solvent in the solutions have been calculated. The results indicate that water side-chain interactions make an important contribution to the solvation of peptides.

Partial molar volumes and heat capacities of the N-acetyl amide derivatives of the amino acids asparagine, glutamine, tyrosine, and lysine monohydrochloride in aqueous solution at temperatures from T=288.15K to T=328.15K

“…The solid product was removed by filtration, washed with ethyl acetate and dried under vacuum at T = 318 K for 24 h. Overall yield 2.8 g (46%); m.p. T = (417 to 418) K. Analysis by alkalimetric titrimetry [20,21] gave a relative molar mass of (223.5 ± 1.2), which is in good agreement with that expected for the anhydrous compound (M r = 223.69). Elemental analyses gave the mass fractions: C, 0.428; H, 0.080; N, 0.188; calculated composition for C 8 H 18 O 2 N 3 Cl: C, 0.430; H, 0.081; N, 0.188.…”

Partial molar volumes and adiabatic compressibilities of glycyl peptides at 25.degree.C

“…Some studies on small peptides of mixed sequence indicate no change in the volume of side groups. 31 In view of the conflicting information and after a careful review of the literature, we conclude that at present the simple subtraction method is by far the most reliable for estimating side-group contributions. The data obtained in this way can be used in conjunction with the Vmo(gly) or Kmo(gly) to calculate the volumes and compressibilities of the unfolded state of proteins.…”

Thermodynamic Properties of Peptide Solutions. 16. Partial Molar Heat Capacities and Volumes of Some Tripeptides of Sequence Gly-X-Gly in Aqueous Solution at 25 °C

“…The product was chromatographically pure as determined by TLC and HPCE. Analysis by alkalimetric titration (Kumaran et al, 1983;Kolthoff and Stenger, 1947) gave a relative molar mass of (298.5 ( 2.1), which is slightly higher than that for the anhydrous compound (M r ) 295.30). Elemental analyses gave C, 52.7%; H, 5.7%; N, 14.1%; cf.…”