[en] The mechanism of reverse kinetic isotopic effect (KIE), observed for reaction of atomic tritium with a mixture of glycine and leucine aminoacids, was investigated. For the purpose peptide (2-²H₂)-glycyl-DL-leucine, synthesized from (²H₅)-glycine and leucine, was used. KIE in reaction of atomic tritium with glycine residue within peptide composition constituted f=α_h/α_d=1.9. For a mixture of free aminoacids the value of f can vary from 0.1 to 0.6

[en] Characteristics of atomic tritium source represented by tungsten wire heated by electric current up to 2000 K in tritium atmosphere at p(T₂)=0.4-4 Pa pressure (atom flux from tungsten surface and energy spectrum of atoms on target) are considered. These characteristics are determined by atomization rate, i.e. by the process activation energy and molecular tritium flux to tungsten surface. It is assumed, that a relative yield of labelled products and intramolecular distribution of tritium under tritium atom effect on organic substances will depend on pressure in the system and diameter of the vessel used, while the spiral temperature should produce a lower effect. Results of action by tritium atoms on indole at different p(T₂) are presented

[en] Interaction of tritium atoms with glycine (1) and leucine (2) amino acids, deuterated amino acids, their mixtures and glycylleucine (3) peptide in the 77-300 K temperature range is studied in isothermal and gradient regimes. Tagged amino acids were separated from targets after conducting the reaction. At T < 100 K high isotope effect and low activation energy point out the tunnel mechanism of the process. At 77 K the ratio of molar radioactivities (1) and (2) in the mixture of amino acids does not depend on the ratio of the components in the target, that speaks to fulfillment of the law of additivity. Noticeable deviations from the law of additivity registered for T > 150 K are associated with intermolecular transmission of free valence in the mixture of amino acids. Regularities of the reaction found for the mixture of amino acids are conserved for (3) as well, i.e. the peptide bond does not essentially affect the reaction of isotopic exchange conditioned by atomic tritium

[en] Method of thermal activation of tritium was used to produce tritium labelled pantethine. Effect of reaction time, molecular tritium pressure and temperature of tungsten wire on the yield of ³H-pantethine and process kinetics was studied

[en] The authors describe reactor designed for the production of atomic tritium and the synthesis of atomic tritium-labelled organic compounds which consists of a spiral tungsten wire as a catalyst for the dissociation of molecular tritium and walls lined with the organic target material. The tritiation of indole is used as a demonstration of the reactor operation. A model is created describing the flow dynamics and thermodynamics within the reactor during the dissociation and labelling process. The chemical aspects of the radioactivation of indole are also assessed

[en] Interaction between tritium atoms, obtained at 2000 K, and the polyethylene film (l=50 cm), boing at essentially lower temperature (290-55 K), is studied. At p=3.33 Pa (³H₂) tritium atoms are shown to be thermalized at the distance of 1 cm. The reaction is carried out: 1) under isothermal conditions; 2) at two temperatures: 290 and 250, 290 and 195, 290 and 77 K; 3) at temperature gradient from 290 to 55 K. Change in film radioactivity with distance and temperature allows to calculate the value of apparent energy of the 17.6+-2.3; 2.0+-0.2; 0.2+-0.3 kJ/mol reaction activation for the temperature range of 290-250, 180-80, 80-55 K. Breaking of the Arrhenius law is explained by ''defrosting'' the radical destruction process and tunneling reactions of hydrogen separation

[en] The interaction is studied of tritium atoms produced at 2000⁰K with polyethylene film (Z = 50 cm), at a considerably lower temperature (290-55⁰K). It is shown that with p = 3.33 Pa (³H₂), the tritium atoms are thermalized (Maxwellized) at a distance of 1 cm. The reaction was conducted: in isothermal conditions; at two temperatures: 290 and 250, 290 and 195, and 290 and 77⁰K; in a temperature gradient from 290 to 55⁰K. The change of radioactivity of the film with distance and temperature allowed the values of the apparent energy of activation of the reaction, 17.6 + or - 2.3; 2.0 + or - 0.2, and 0.2 + or - 0.3 kJ/mole to be calculated for the temperature ranges 290-250, 180-80, and 80-55⁰K. The breakdown of Arrhenius' law is explained by the ''defrosting'' of the process of radical destruction, and tunnel reactions of the detachment of hydrogen

No abstract available

[en] A study has been made of the feasibility of using thermal activation of tritium to investigate the processes involved in the formation of adsorbed peptide layers. In the example of glycylleucine, changes in orientation of the dipeptide molecule have been followed in the process of forming an adsorbed surface layer. Study of the intramolecular distribution of tritium has suggested two possible types of orientation of this peptide that are accomplished in rarefied and saturated adsorbed layers

No abstract available