MODELING OF TRANSFER PROPERTIES USING REVISED HKF-THEORY - THERMODYNAMICS OF TRANSFER OF AN AMINO-ACID AND SMALL PEPTIDES FROM WATER TO UREA-WATER SOLUTIONS AT 298.15-K

Relative densities (rho - rho(1)(0)), and heat capacity ratios, (c(p) rho/(c(p1)(0) rho(1)(0)) - 1), have been measured for aqueous solution s of glycine, glycylglycine, and glycylglycylglycine in aqueous urea s olutions containing 1-13 mol kg(-1) urea. These data have been used to calculate apparent molar volumes, V-2,V-phi, and apparent molar heat capacities, C-p2,C-phi, which in turn have been used to obtain standar d state volumes, <(V)over bar (0)(2)>, and standard state heat capacit ies, <(C)over bar (0)(p2)>. Volumes and heat capacities of transfer fr om water to urea have been calculated from our reported standard state data. Heat capacities of transfer of the investigated systems have be en modeled using a procedure developed from the semiempirical calculat ion procedures proposed by Helgeson, Kirkham, and Flowers.