Nanotek & Expo

Biography

Biography: Vitaly Ovchinnikov

Abstract

The values of free energies and the heats of combustion and formation in condensed and aqua phases of some amino acids of different structure and some peptides of the low molecular weight were analyzed on the topics of their interactions each to other and hydrolysis decomposition. The equation of such type as Hо = i ± f (N – g), in which Hо is the heat, i and f are stoichiometric coefficiens, N is the number of valence electrons, from which a number of lone electron pairs (g) is excepted for, has been made. The obtained equation were used for the calculations of a new such parameters for four amino acids in water continuum. Results and Discussion: It is known, that according to the data of the monography [1], the classification of the structures of any amino acids it is possible to divide into some groups [2]. The first of them form such acids, which contain non ionic lateral chains in their constitution: they are I – glycine (Gly), II – L-alanine (Ala), III – valine (Val), IV – L-threonine (Thr). The formation heats in aqua solution (∆aqHo) of compounds (I-IV) could be founded as the sum of the heats in the condensed state (∆fHo) and the heats of solution (∆solnHo) of acids in water medium (Equation 1) ∆aqHo = ∆fHo + ∆solnHo (1). These data are: for I -528.5, -14.2, -542.7; for II -559.5, -9.7, -569.2; for III -628.9, -5.2, -634.1; for IV -563.0, -9.6, -572.6 kJ mol-1 correspondingly. These data gave us a possibility to calculate the equation (2), in which N is the number of valence electrons and g is the number of lone pairs of heteroatoms (N: and :O:) ∆aqHo = (-488.0 ± 18.2) – (4.9 ± 0.9) (N-g); r 0.967, So 12.1, n 4 (2). Using Eq. (2), we calculated the values ∆aqHo for amino acids of the same group: for V – phenylalanine (Phe ) -703.6, for VI – leucine (Leu) -654.6 and VII – tyrosine (Tyr) -693.8 kJ mol-1 correspondingly. The all data are necessary for the calculation of the heats of hydrolysis reactions (2-5) of the condensed peptides (∆fHo) with a low molecular weight and: VIII – Glycilglycine (Glygly, -747.7), IX - N-dl-Alanilglycine (Alagly, -777.4), X - N-(N-glycilglycil)glycine N-(Glyglygly, -813.0) and XI – the human hormone (TyrGlyGlyPheLeuOH, -2258 kJ mol-1 correspondingly). The heat of condensed water value is equal -285.8 kJ mol-1. Glygly + H2O (l)  2 Gly(aq) (2) Alagly+ H2O (l)  Gly(aq) + Ala(aq) (3) Glyglygly+2 H2O (l)  3 Gly(aq) (4) TyrGlyGlyPheLeuOH+4 H2O (l)  Tyr(aq)+ 2 Gly(aq) + Phe(aq) + Leu(aq) (5) The heats of reactions (2-5) are -51.9, -48.7, -243.5 and -264.2 kJ mol-1 correspondingly. The receiving results show that low molecular peptides easy and exothermically hydrolyze in water. The middle between the first two values (-53.9 ± 4.2 kJ mol-1) can be accepted as an energy of the peptide bond.