The relevance of studying the regulation of protein-ligand interactions is due to the emergence of new views on the role of metabolites and their key importance in vital processes. To study the protein-ligand interaction, the AB0 antigen-antibody blood system and the enzyme-substrate system of dehydrogenases were used as a test system, and ethanol was used as an influencing factor. In experiments performed with A and B blood erythrocyte antigens, natural AB0 system antibodies and monoclonal antibodies under the influence of ethanol performed change of the degree of agglutination and the time to onset of erythrocyte agglutination. It was found that ethanol can regulate the enzyme-substrate interactions of dehydrogenases: lactate dehydrogenase (EC 1.1.1.27), glyceraldehyde phosphate dehydrogenase (EC 1.1.1.12), and α-glycerol phosphate dehydrogenase (EC 1.1.1.8). The increase in the activity of studied enzymes under the influence of ethanol in the whole blood hemolysate was 2.5 - 3 times higher than in the isolated medium (with pure enzyme preparations).

The aim of this work was to study the conformational changes of lactate dehydrogenase under the influence of different concentrations of intermediates (pyruvate, oxaloacetate) in the temperature gradient with the subsequent building of a mathematical model.Materials and methods. Thermolability of lactate dehydrogenase was studied using the method of differential scanning fluorimetry to determine the change in endogenous fluorescence of tryptophan and tyrosine under the conditions of stable concentration of lactate dehydrogenase and changing concentrations of pyruvate and oxaloacetate. Further, a mathematical model was developed for a more in-depth consideration of the behavior of the catalytic protein.Results. We found that pyruvate and oxaloacetate in low concentrations have a thermostabilizing effect on lactate dehydrogenase conformation; the effect of pyruvate is statistically more significant in comparison with oxaloacetate (p < 0.05). The studied ligands in high concentrations reduce the thermal stability of lactate dehydrogenase.Conclusion. Understanding the role of small molecules in the regulation of biological and catalytic processes has long remained in the background of scientific interest, but today the work in this direction is reaching a new level. The data obtained indicate the possibility of small molecules acting as ligands when interacting with enzymes.

The aim of this work was to study the conformational changes of lactate dehydrogenase under the influence of different concentrations of intermediates (pyruvate, oxaloacetate) in the temperature gradient with the subsequent building of a mathematical model. Materials and methods. Thermolability of lactate dehydrogenase was studied using the method of differential scanning fluorimetry to determine the change in endogenous fluorescence of tryptophan and tyrosine under the conditions of stable concentration of lactate dehydrogenase and changing concentrations of pyruvate and oxaloacetate. Further, a mathematical model was developed for a more in-depth consideration of the behavior of the catalytic protein. Results . We found that pyruvate and oxaloacetate in low concentrations have a thermostabilizing effect on lactate dehydrogenase conformation; the effect of pyruvate is statistically more significant in comparison with oxaloacetate ( p < 0.05). The studied ligands in high concentrations reduce the thermal stability of lactate dehydrogenase. Conclusion. Understanding the role of small molecules in the regulation of biological and catalytic processes has long remained in the background of scientific interest, but today the work in this direction is reaching a new level. The data obtained indicate the possibility of small molecules acting as ligands when interacting with enzymes.

Самарский государственный медицинский университет, Самара, Российская Федерация (1) Российский университет дружбы народов

Российский университет дружбы народов, Москва

For the first time we studied the effect of the anticancer drug L-lysine-a-oxidase, obtained from culture liquid of Trichoderma harzianum Rifai F-180. In vitro experiments we established the high activity of L-lysine-a-oxidase in a model of tick-borne encephalitis and the lack of activity against viruses Sindbis, West Nile, Tahyna and Dhori.

2 ФГБОУ ВПО «Российский университет дружбы народов», Москва В последнее десятилетие изучение взаимодействий белка с малыми молекулами и метаболитами было запаздывающим по сравнению с изучением других типов взаимодействий, таких как белок-белковое, белок-ДНК и белок-РНК.На новом этапе изучения проблемы, благодаря научным и технологическим достижениям, мы начали исследовать влияние малых молекул на межмолекулярные взаимодействия

The analysis of published data showed the necessity and urgency of research of theinteraction specificity of small and large molecules that might have a regulatory value. In in vitro conditions we were studying the effect of ethanol on the activity of dehydrogenases: glyceraldehyde phosphate dehydrogenase GAPDH (EU 1.2.1.12), alpha-glycerol phosphate dehydrogenase - alpha -GPD (EU 1.1.1.8) and lactate dehydrogenase LDH (EU 1.1.1.27) - in the hemolysate of red blood cells and in the isolated homogeneous enzymes. A comparative evaluation of enzyme activity after their incubation with ethanol in the hemolysate and in the isolated environment showed that the activity of GAPDH, alpha-GPD and LDH increased in both media, but in a quantitative ratio the enzyme activity in isolated the environment was considerably smaller than in the hemolysate - multicomponent medium. Thus, during the metabolic adaptation to the effect of external stimulus the efficiency of all studied dehydrogenases increases. Ethanol can play the role of regulator of molecular processes of metabolism by modulating the enzyme-substrate interaction.

Самарский национальный исследовательский университет имени академика С

In many animals on the erythrocytes are present group antigens similar to the antigens of the system AB0 human. Immunogenetic features of blood does not change throughout the life of the animal. Primates have different combinations of blood group 0, А, В and AB. Described the various systems of blood groups of farm animals: cattle - 12, sheep - 7, in pigs - 17, horses - 7. There are 14 systems of blood groups and more than 60 antigens in chickens. In dogs described 10 systems of blood groups, cats 3. Blood group systems allow you to combine one animal species in certain groups according to the similarity of their blood antigens.

During the study of the supernatants homogenates among Ixode, relapsing-fever blood-sucking ticks belonging to five different genera and ten species in polyacrylamide gel by electrophoresis the species differences were revealed in electrophoretic mobility of the tick protein fractions. Relapsing-fever ticks demonstrate as generic so as specific differences during the nymphal stage of development. The nymphs 3 Ornithodoros papillipes contain two protein fractions, O. moubata contain 3 fractions and Alveonasus lahorensis contain 5 fractions. The same kind of ticks had the same amount of protein fractions at the electrophoretic separation of proteins. During the larval stage the homogenates of ticks always show one protein fraction. The hemolymph of A. lahorensis tick showed the differences between imago and nymph 3. The antibacterial activity of the supernatant homogenate mite is revealed. The correlation between the value of antibacterial activity of the supernatant homogenate of ticks and the amount of protein fraction is showed at the electrophoresis in polyacrylamide gel. A new biochemical marker is proposed to state the species of ticks.

Using the ABO antibody-antigen model the influence of natural metabolite pyruvate on the antibody interaction with of erythrocyte antigens, defining their group specificity has been investigated. Before agglutination reaction erythrocytes of A(II)-AB(IV) blood groups, monoclonal anti-A and anti-B antibodies were incubated with sodium pyruvate. Visualization of agglutinates was performed by means of flow cytometry and laser scanning confocal microscopy. Computer-aided prediction of the spectrum of biological activity of pyruvate by a PASS program proposed major regulatory pathways, in which pyruvate may be involved. It has been demonstrated that pyruvate can regulate the intensity of antigen-antibody interaction. These results suggest the possibility of using small molecules, for example pyruvate, as molecular probes and prospects of the use of erythrocytes with antigenic determinants of the ABO system expressed on their membranes for studies of protein-protein interactions due to convenient visualization and possibility of quantitative evaluation of this process.

Using the AB0 antibody-antigen model the influence of natural metabolite pyruvate on the antibody interaction with of erythrocyte antigens, defining their group specificity has been investigated. Before agglutination reaction erythrocytes of A (II)–AB (IV) blood groups, monoclonal anti-A and anti-B antibodies were incubated with sodium pyruvate. Visualization of agglutinates was performed by means of flow cytometry and laser scanning confocal microscopy. Computer-aided prediction of the spectrum of biological activity of pyruvate by a PASS program proposed major regulatory pathways, in which pyruvate may be involved. It has been demonstrated that pyruvate can regulate the intensity of antigen-antibody interaction. These results suggest the possibility of using small molecules, for example pyruvate, as molecular probes and prospects of the use of erythrocytes with antigenic determinants of the ABO system expressed on their membranes for studies of protein-protein interactions due to convenient visualization and possibility of quantitative evaluation of this process.