Enthalpic Interaction Model Molecule For Several Proteins

The protein occupies the special position in the living creature body, and is the material foundation that the morphosis and the life activities of the organism depend on. But because of the very complicated factor that determine the protein structures in all kinds of solvents,the direct research of the protein is limited.Hence people change the study direction to the protein model members.Now the aqua thermodynamics study of the protein members with the amino acids,amides,peptide and its derivatives has caused the researcher's extensive value.This paper mainly consists of the following five parts.The first part summarizes the general states of studies on the thermodynamic properties of systems containing protein model molecules.In the second part, enthalpies of mixing of aqueous amino acids solutions (glycine, L-alanine, L-serine, L-valine, L-proline, L-threonine) with aqueous cyclols solutions (inositol, cyclohexanol) have been determined at 310.15K by 2277 flow microcalorimetric system. These results along with enthalpies of dilution of these aqueous solutions have been used to obtain the enthalpic interaction coefficients (h_xy, h_xxy, h_xyy) in terms of the McMillan-Mayer theory. The pairwise interactions between amino acids and cyclols have been discussed by solute-solute interaction theory.In the third part, the enthalpic pairwise interactions between six kinds of amino acids and amides (formamide,N, N-dimethyformamide) have been determined at 310.15K.In the forth part, the enthalpic pairwise interactions between five kinds of amides and heterocycle compounds (tetrahydrofuran,1, 4-dioxane) have been determined at 310.15K. These results along with enthalpies of dilution of these aqueous solutions have been used to obtain the enthalpic interaction coefficients (h_xy, h_xxy, h_xyy) in terms of the McMillan-Mayer theory.The fifth part consists of the following two sections.(1) Enthalpies of mixing of aqueous glycine solutions with aqueous picolines solutions (2-picoline, 3-picoline,4-picoline) have been determined at 298.15K by 2277 flow microcalorimetric system. These results along with enthalpies of dilution of these aqueous solutions have been used to obtain the enthalpic interaction coefficients (hxy, hxxy, hxyy) in terms of the McMillan-Mayer theory.(2) The hydrogen bonding of 1:1 complexes formed between glycine and three kinds of isomers of picolines have been completely investigated using B3LYP method at varied basis set levels from 6-31G to 6-31+G(d). The results shows that the interaction energies of hydrogen bond complexes between amino acids and picoline isomers have great effects on the values of hxy. The stronger the interaction energy is, the smaller is the value of hxy.