AFFINIMETER kinetics

KinITC is a new method implemented in AFFINImeter to obtain kinetic information from ITC data. With one single titration experiment it calculates the full thermodynamic (KA and ΔH) and kinetic profiling (kon and koff) of 1:1 binding interactions. It reads data from TA and Microcal calorimeters

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Get full kinetic and thermodynamic profiling of interactions from standard ITC data. You don't need to perform additional or specific experiments to obtain kinetics so, you can analyze right away old ITC data with our free trial.

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AFFINImeter allows the introduction of new applications to ITC experiments

It is quite often that ligands are synthetized as a mixture of isomers, and that they bind to the same receptor. In some cases, it is not easy to detect different binding events with a simple experiment. In such cases, it is recommended to perform a reverse titration experiment where the mixture of ligands is placed in the cell and the receptor is titrated from the syringe. AFFINImeter allow to globally fit both isotherm with linked thermodynamic parameters.

Global Analytis Reverse Titration Thermogram

AFFINImeter present great advantages in ITC displacement assays: It allows to analyze competitive measurements even if the tight-ligand and the competitor are placed in the syringe and offers a global fitting of multiple data series sharing various thermodynamic parameters. This functionality enhance the robustness of the method and makes it more versatile, facilitating the acquisition of reliable thermodynamic data from ultra-high of ultra-low affinity systems.

Competitive Interaction Experimental ITC Isotherms

AFFINImeter provides a "Model Builder" to create your own binding models without limitation in the stoichiometry. Complex binding interactions involving up to three species can easy be written in an easy-to-use interface. Such complex systems require global fit several isotherms measured at different experimental conditions to avoid overparametrization of the fitting procedure. AFFINImeter also calculate the species distribution of all the complex present in the cell over the titration for a better interpretation of the results.

Competitive Interaction Experimental ITC Isotherms
Competitive Interaction Experimental ITC Isotherms

Conformational changes induced by binding can be essential in biological processes; such as DNA/RNA condensation, induced-fit antigen binding in immunoglobulins, protein denaturation, polyplexes formation or enzyme catalysis. The mayor handicap in the analysis of the ITC isotherms in these systems lays on the overlap of the endothermic/exothermic heat released in the binding and in the conformational changes.

Ligand-induced conformational changes

AFFINImeter provides specific models to analyze conformational changes sequenced with binding interactions.

This model in under development. Contact us if you are interested to try it

AFFINImeter includes three different parameters that can account as corrections of the concentrations for the receptor and for each ligand (rm, ra and rb). These parameters can be independently fitted if any of the concentrations of the species involved in the reaction is uncertain. Moreover, AFFINImeter can successfully analyze ITC data of an interaction between a receptor with a heterogeneous mixture of ligands (isomers, heteropolymers, oligomers, etc..) even if the proportional concentrations of the ligands are unknown for the user.

AFFINImeter not only can analyze binding interactions, also can be used to analyze aggregation/dissociation progresses with the advantage that there is no limitation in the number of aggregates. It is also possible to combine binding reactions with aggregation to analyze, for instance, dimerization induced by binding.

Aggregation and micellization studies

An extension of this model can be used to obtain a complete thermodynamic characterization of the demicellization processes including the heat of dilution of surfactant monomers and micelles, as well as the enthalpy and the Gibbs energy changes for the molecular transfer from the solution to the aggregates. This model is under development, but if you are interested in analysis your demicellization data, please, contact us

Aggregation and micellization studies