Tag Archives: rate constants
Thermodynamics of interaction between polyreactive immunoglobulins and immobilized antigen
S. A. Bobrovnik1*, O. V. Ogloblya2, M. O. Demchenko1, S. V. Komisarenko1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2ESC Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Ukraine;
*e-mail: s-bobrov@ukr.net
Received: 22 April 2021; Accepted: 22 September 2021
In order to determine thermodynamic parameters of the interaction between polyreactive immunoglobulins (PRIGs) and immobilized antigen, several of experimental kinetic curves of PRIGs binding to immobilized ovalbumin were obtained at different temperatures. This allowed determining the rate constants for every step of the binding process for each temperature. Then, using appropriate equations, thermodynamic parameters, such as activation energy, enthalpy, entropy, and standard free energy (Gibbs energy), were calculated. Thermodynamic values obtained show that the main energy consuming step in the study process of PRIGs bindingis the transformation of “inactive” PRIGs into “active” PRIGs, i.e. formation of hydrophobic patches on the surface of PRIGs molecules. In contrast, the following step of the binding of “active” PRIGs to an immobilized antigen is not an energy dependent process.
Kinetics of interaction between polyreactive immunoglobulins and antigen
S. A. Bobrovnik1*, O. V. Ogloblya2, M. O. Demchenko1, S. V. Komisarenko1
1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
2ESC “Institute of Biology and Medicine”, Taras Shevchenko National University of Kyiv, Ukraine;
*e-mail: s-bobrov@ukr.net
Received: 28 January 2020; Accepted: 25 June 2020
A number of experimental kinetics curves of mice polyreactive immunoglobulins (PRIGs) binding to ovalbumin immobilized on immunologic plates were obtained at different temperatures. Analysis of these curves allowed us to conclude that the model of PRIGs interaction with antigens proposed by us earlier and consisted on PRIGs activation (i.e. exposition of hydrophobic patches on PRIGs surface) and either sequential binding to antigen or inactivation was is in a good agreement with the experimental data obtained in this study. We have designed a method of the rate constants evaluation from experimental binding curves. It was found that the rate constant of the activated PRIGs binding to immobilized antigen did not depend on temperature. The rate constant of PRIGs activation occurred to be depend on temperature more strongly than the rate constant of PRIGs inactivation. We have concluded from the acquired dependences that at 37°С the number of activated PRIGs was 15 times higher than that at 0°С.
Kinetics of interaction between polyreactive immunoglobulins and antigen. The theory
S. A. Bobrovnik, M. O. Demchenko, S. V. Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@ukr.net
Received: 14 February 2019; Accepted: 17 May 2019
Dynamics of association between polyreactive immunoglobulins (PRIGs) and immobilized antigens is considered on the base of our model of PRIGs-antigen interaction, which was suggested by us earlier. This process of PRIGs binding to an immobilized antigen was described with a system of differential equations. The solution of this system of differential equations gives mathematical expressions that relate the dynamics of the reactant concentrations and time of the reaction. Using Microsoft Excel program the theoretical curves were calculated and plotted that described the dynamics of “active”, “nonactive” PRIGs in solution as well as PRIGs that were bound to an immobilized antigen. Conclusions drawn by us earlier about very high dependence of reaction PRIGs with an antigen from temperature were confirmed.
New approach in evaluating affinity of bivalent antibodies by the method of surface plasmon resonance. Theory
S. A. Bobrovnik, M. O. Demchenko, S. . Komisarenko
Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: s-bobrov@bk.ru
Theoretical aspects of the affinity evaluation for the interaction between bivalent receptors (or antibodies) and corresponding ligands (or antigens) are considered. It was shown that the ligand presence in the solution at the stage when the receptor dissociation occurs leads to the increase of the affinity evaluation accuracy. We demonstrated that the analysis of the dissociative curve of the receptor from the chip is not necessary for affinity determination; the analysis of associative curve is sufficient for this purpose. We also suggested a new approach for evaluating the affinity of bivalent receptors (or antibodies) when these reagents are present in the studied solution and the correspondent ligand (or antigen) is immobilized on the chip.