[Calorimetric study of the interaction between amino acids and sugars in water at 298.15 K]. / Kalorimetricheskoe issledovanie vzaimodeistvii mezhdu aminokislotami i sakharidami v vode pri 298.15 K.

The enthalpies of dissolving glycine and DL-alanine in water solutions of D-glucose, D-maltose, and sucrose at 298.15 K were determined by calorimetry. From the results obtained, the coefficients of enthalpy for pairwise interactions hxy of the amino acids and saccharides in water were calculated. It was found that the hxy values for glycine in solutions of all saccharides studied are negative; in the case of DL-alanine, the hxy values are positive for all saccharides except for sucrose solution. It was shown that the hxy values reflect the sum effect of interactions between the amino acids and saccharides in aqueous solutions and the contribution of hydration of the solutes.

[Enthalpy of interaction of amino acids and peptides with 6-azauracil in water]. / Ental'piia vzaimodeistviia aminokislot i peptidov s 6-azauratsilom v vode.

We have determined the enthalpies of dissolution of 6-azauracil in aqueous solutions of amino acids and peptides at the 25 degrees C, and the enthalpic coefficients of their pair interactions in water have been calculated on the basis of McMillan-Mayer formalism. The analysis of hydration of zwitterion and side chain of amino acids and peptides on an interaction character has been done. The comparison of the interaction coefficients of 6-azauracil with amino acids and the linear peptides shows that this interaction is localized near the one of zwitterion charged groups.