Thermochemistry of Heteroatomic Compounds: Analysis and Calculation of Thermody-namic Functions of Amino Acids and Some Peptides of Different Space Structure

Abstract

The values of free energies, the heats of combustion and formation in condensed and gaseous phases over 30 amino acids of different structure were analyzed. Entropies and heat capacities in standard conditions were considered too. Twenty one equations of such type as Yо = i ± f (N – g) +Σ(hc)j, in which Yо is thermodynamic function or heat capaci-ty, i and f are stoichiometric coefficiens, Σ(hc)j are the sums of the number (j) of the heat corrections for the mentioned thermodynamic magnitudes, N is the number of valence electrons, from which a number of lone electron pairs (g) is ex-cepted for. The obtained equations were used for the calculations of a new such parameters for four phosphorylated amino acids, two enkephalines and two human peptides of low molecular weights.