The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Yu. Ya. Fialkov - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic characteristics of the ionic Association Process of acids in aqueous solutions
Journal of Molecular Liquids, 2003Co-Authors: Yu. Ya. Fialkov, V. Yu. Gorbachev, T.a. KamenskayaAbstract:Abstract In this work thermodynamic characteristics of the ionic Association Process for a series of organic and inorganic acids in aqueous solutions have been analysed. The advantage of division of the thermodynamic characteristics into true (‘van't Hoff's’) and dielectric components over integral values for equilibria analysis in solutions has been demonstrated.
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Thermodynamic data interpretation of the ion Association Process in mixed solvents
Journal of Molecular Liquids, 2000Co-Authors: Yu. Ya. Fialkov, V. L. ChumakAbstract:Abstract Some approaches have been developed which allow to divide thermodynamic functions of the ion Association Processes in two components. The first component belongs to the Process, the second one is caused by the temperature dependence of the dielectric permittivity of the solvent. The theory is confirmed by numerous examples which deal with the ion Association Process of different electrolytes in binary mixed solvents.
T.a. Kamenskaya - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic characteristics of the ionic Association Process of acids in aqueous solutions
Journal of Molecular Liquids, 2003Co-Authors: Yu. Ya. Fialkov, V. Yu. Gorbachev, T.a. KamenskayaAbstract:Abstract In this work thermodynamic characteristics of the ionic Association Process for a series of organic and inorganic acids in aqueous solutions have been analysed. The advantage of division of the thermodynamic characteristics into true (‘van't Hoff's’) and dielectric components over integral values for equilibria analysis in solutions has been demonstrated.
Alexey Kopylov - One of the best experts on this subject based on the ideXlab platform.
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Putative Mechanisms Underlying High Inhibitory Activities of Bimodular DNA Aptamers to Thrombin.
Biomolecules, 2019Co-Authors: Elena Zavyalova, Valeriia A. Legatova, Rugiya Sh. Alieva, Arthur O. Zalevsky, Vadim N. Tashlitsky, A. M. Arutyunyan, Alexey KopylovAbstract:Nucleic acid aptamers are prospective molecular recognizing elements. Similar to antibodies, aptamers are capable of providing specific recognition due to their spatial structure. However, the apparent simplicity of oligonucleotide folding is often elusive, as there is a balance between several conformations and, in some cases, oligomeric structures. This research is focused on establishing a thermodynamic background and the conformational heterogeneity of aptamers taking a series of thrombin DNA aptamers having G-quadruplex and duplex modules as an example. A series of aptamers with similar modular structures was characterized with spectroscopic and chromatographic techniques, providing examples of the conformational homogeneity of aptamers with high inhibitory activity, as well as a mixture of monomeric and oligomeric species for aptamers with low inhibitory activity. Thermodynamic parameters for aptamer unfolding were calculated, and their correlation with aptamer functional activity was found. Detailed analysis of thrombin complexes with G-quadruplex aptamers bound to exosite I revealed the similarity of the interfaces of aptamers with drastically different affinities to thrombin. It could be suggested that there are some events during complex formation that have a larger impact on the affinity than the states of initial and final macromolecules. Possible mechanisms of the complex formation and a role of the duplex module in the Association Process are discussed.
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How does Association Process affect fibrinogen hydrolysis by thrombin
Biochimie, 2014Co-Authors: Elena Zavyalova, Alexey KopylovAbstract:Abstract Thrombin, a key enzyme in the blood coagulation cascade, hydrolyzes fibrinogen into fibrin, which specifically associates into the fibers that build up a thrombus scaffold. The assembly of fibrin involves a set of stepwise reactions, for which a complete and detailed kinetic portrait is needed. Existing kinetic models focus on particular parts of the Process, for example the mechanism of enzyme action itself or the kinetics of formation of fibrin assemblies. The current study considers a thorough model of the Process from fibrinogen hydrolysis to the assembly of fibrin. Composing the model requires taking into account several reaction intermediates, stepwise removal of fibrinopeptides, and Association of partially hydrolyzed fibrin, in particular desAA fibrin. The model is versatile enough to adopt new data both on fibrinogen hydrolysis and fibrin Association. In addition, the model could be considered as an example of a kinetic description of other complex enzyme systems having several intermediates and feedbacks, such as the blood coagulation cascade and signal transduction.
Elena Zavyalova - One of the best experts on this subject based on the ideXlab platform.
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Putative Mechanisms Underlying High Inhibitory Activities of Bimodular DNA Aptamers to Thrombin.
Biomolecules, 2019Co-Authors: Elena Zavyalova, Valeriia A. Legatova, Rugiya Sh. Alieva, Arthur O. Zalevsky, Vadim N. Tashlitsky, A. M. Arutyunyan, Alexey KopylovAbstract:Nucleic acid aptamers are prospective molecular recognizing elements. Similar to antibodies, aptamers are capable of providing specific recognition due to their spatial structure. However, the apparent simplicity of oligonucleotide folding is often elusive, as there is a balance between several conformations and, in some cases, oligomeric structures. This research is focused on establishing a thermodynamic background and the conformational heterogeneity of aptamers taking a series of thrombin DNA aptamers having G-quadruplex and duplex modules as an example. A series of aptamers with similar modular structures was characterized with spectroscopic and chromatographic techniques, providing examples of the conformational homogeneity of aptamers with high inhibitory activity, as well as a mixture of monomeric and oligomeric species for aptamers with low inhibitory activity. Thermodynamic parameters for aptamer unfolding were calculated, and their correlation with aptamer functional activity was found. Detailed analysis of thrombin complexes with G-quadruplex aptamers bound to exosite I revealed the similarity of the interfaces of aptamers with drastically different affinities to thrombin. It could be suggested that there are some events during complex formation that have a larger impact on the affinity than the states of initial and final macromolecules. Possible mechanisms of the complex formation and a role of the duplex module in the Association Process are discussed.
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How does Association Process affect fibrinogen hydrolysis by thrombin
Biochimie, 2014Co-Authors: Elena Zavyalova, Alexey KopylovAbstract:Abstract Thrombin, a key enzyme in the blood coagulation cascade, hydrolyzes fibrinogen into fibrin, which specifically associates into the fibers that build up a thrombus scaffold. The assembly of fibrin involves a set of stepwise reactions, for which a complete and detailed kinetic portrait is needed. Existing kinetic models focus on particular parts of the Process, for example the mechanism of enzyme action itself or the kinetics of formation of fibrin assemblies. The current study considers a thorough model of the Process from fibrinogen hydrolysis to the assembly of fibrin. Composing the model requires taking into account several reaction intermediates, stepwise removal of fibrinopeptides, and Association of partially hydrolyzed fibrin, in particular desAA fibrin. The model is versatile enough to adopt new data both on fibrinogen hydrolysis and fibrin Association. In addition, the model could be considered as an example of a kinetic description of other complex enzyme systems having several intermediates and feedbacks, such as the blood coagulation cascade and signal transduction.
Yves Claude Guillaume - One of the best experts on this subject based on the ideXlab platform.
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Triazine-human serum albumin Association: thermodynamic approach and sodium effect.
Journal of Chromatography B - Analytical Technologies in the Biomedical and Life Sciences, 2002Co-Authors: Lhassane Ismaili, Claire André, Mireille Thomassin, Tong Thanh Truong, Joelle Millet, Laurence Nicod, Eric Cavalli, Jean Pierre Chaumont, Alain Xicluna, Yves Claude GuillaumeAbstract:Human serum albumin (HSA) serves as a carrier protein to transport triazine herbicides to molecular targets. In this paper, a theoretical treatment was developed to describe the HSA-triazine herbicides Association. A determination of the Association constant, K, as well as the degree of complexation n(c) (the percent of complex guest) was carried out. Enthalpy-entropy compensation was also analyzed in relation to this mathematical model to confirm the herbicide complexation behavior with HSA. The role of the sodium cation (Na(+)) on this Association was investigated. It was expected that the sodium ion would act on the herbicide-HSA Association Process by modifying the surface tension of the bulk solvent and increase the K and n(c) values. The results showed that for patients who suffer from Na(+) desequilibrium, the triazine-HSA binding would change and as well the toxicological effect of these herbicides.
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Role of the Na+ ion on phenol derivatives/hydroxypropyl-beta-cyclodextrin complex formation on porous graphitic carbon phase.
Journal of Chromatography A, 2002Co-Authors: Yves Claude Guillaume, Tong Thanh Truong, Joelle Millet, Laurence Nicod, Jean Charles Rouland, Mireille ThomassinAbstract:The reversed-phase liquid chromatography retention of phenol derivatives was investigated over a concentration range of sodium chloride (0-10(-2) M) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) (0-35x10(-3) M) using a porous graphitic carbon (PGC) stationary phase and a methanol/water mixture (50:50 (v/v)) as the mobile phase. A theoretical treatment was developed to investigate the effect of the sodium chloride and hydroxypropyl-beta-cyclodextrin on the equilibrium between the solutes with the PGC surface and the aqueous medium, respectively. The thermodynamic parameter variations were calculated using van't Hoff plots. It was expected that the sodium ion acted on the solute-PGC Association Process by modifying the surface tension of both the bulk solvent and the PGC surface. The phenol derivative/HP-beta-cyclodextrin complexation was shown to be entropically controlled for all the solutes except for the one which contained the -NO2 group in its structure, i.e. the nitro phenol derivative. A comparison of the compensation temperature of the solute-PGC Association Process when sodium chloride and HP-beta-CD concentration changed in the mobile phase led to the conclusion that these two modifiers acted via a variation in the hydrophobic effect.
