Influence of Dynamic Power Compensation in an Isothermal Titration Microcalorimeter (original) (raw)
Related papers
Methods in Cell Biology, 2008
Abstract Isothermal titration calorimetry (ITC) is now routinely used to directly characterize the thermodynamics of biopolymer binding interactions and the kinetics of enzyme-catalyzed reactions. This is the result of improvements in ITC instrumentation and data analysis software. Modern ITC instruments make it possible to measure heat eVects as small as 0.1 mcal (0.4 mJ), allowing the determination of binding constants, K's, as large as 10 8 -10 9 M À1 . Modern ITC instruments make it possible to measure heat rates as small as 0.1 mcal/sec, allowing for the precise determination of reaction rates in the range of 10 À12 mol/sec. Values for K m and k cat , in the ranges of 10 À2 -10 3 mM and 0.05-500 sec À1 , respectively, can be determined by ITC. This chapter reviews the planning of an optimal ITC experiment for either a binding or kinetic study, guides the reader through simulated sample experiments, and reviews analysis of the data and the interpretation of the results.
Biological Applications of Isothermal Titration Calorimetry
Physical Chemistry Research, 2015
Most of the biological phenomena are influenced by intermolecular recognition and interaction. Thus, understanding the thermodynamics of biomacromolecule ligand interaction is a very interesting area in biochemistry and biotechnology. One of the most powerful techniques to obtain precise information about the energetics of (bio) molecules binding to other biological macromolecules is isothermal titration calorimetry (ITC). In a typical ITC experiment, a macromolecule solution is titrated by a solution containing a reactant at a constant temperature, and exchanged heat of the reaction is measured, allowing determination of thermodynamic parameters (enthalpy change, entropy change, change in Gibbs free energy, binding affinity and stoichiometry) of molecular interactions. In this review article, we describe the ITC approach briefly and review some applications of ITC for studying protein-ligand interactions, protein-protein interactions, self-association, and drug design processes. Fu...
Current applications of isothermal titration calorimetry to the study of protein complexes
The absorption or liberation of heat has proven a widely spread property in biomolecular processes. Isothermal titration calorimetry (ITC) measures this property directly. This feature not only implies high precision in determining the binding enthalpy, but also allows us to infer the reaction mechanism in a more objective way than many non-calorimetric techniques. In this chapter, the principles of ITC are reviewed together with the basic thermodynamic formalism on which the technique is based. In addition, the current state of the art in calorimetry in protein recognition is described, with particular emphasis on advances in the last few years.
Pure and Applied Chemistry, 2008
Isothermal titration calorimetry (ITC) is widely used to determine the thermodynamics of biological interactions including protein-protein, small molecule-protein, protein-DNA, small molecule-DNA, and antigen-antibody interactions. An ITC measurement consists of monitoring the transfer of heat between an analyte solution in a sample vessel and a reference solution in a reference vessel upon injection of a small aliquot of titrant solution into the sample vessel at a fixed ITC operating temperature. A binding isotherm is generated from the heat-transferred-per-injection data and values for the binding constants, the apparent binding enthalpies, and the apparent ratio of the amount of titrant to analyte for the binding reaction are then determined from fits of a binding model, whether it is a single site, identical multi-site, or an interacting multi-site binding model, to the binding isotherm. Prior to the fitting procedure, corrections should be made for contributions from extraneou...
Isothermal titration calorimetry: A thermodynamic interpretation of measurements
The Journal of Chemical Thermodynamics, 2012
Isothermal titration calorimeters have been developed and in use since the 1960s and the number of applications based on empirical rules to use them steadily increases. In this paper a rigorous study of the physical interpretation of the titration heat and the thermodynamic framework underlying isothermal titration calorimetry are proposed. For infinitesimal titrations, the titration heat is independent of the cell type employed, and the interpretation of the titration heat depends on the titrant composition and on the experiment type. Moreover, for the study of the interaction between two solutes in solution, only a combination of two experiments is necessary, and the result is interpreted as the partial enthalpy of interaction at infinite dilution of the solute contained in the titrant solution.
Multithermal titration calorimetry: A rapid method to determine binding heat capacities
Biophysical Chemistry, 2006
Herein a new method that allows binding DCp to be determined with a single experiment is presented. Multithermal titration calorimetry (MTC) is a simple extension of isothermal titration calorimetry (ITC) that explicitly takes into account the thermal dependences of DH and the binding constant. Experimentally, this is accomplished by performing a single stepwise titration with ITC equipment, allowing temperature readjustments of the system at intermediate states of the titration process. Thus, from the resulting multitherm, DCp can also be determined. The experimental feasibility of MTC was tested by using the well-characterized lysozyme -chitotriose complex as a model system. D
Isothermal titration calorimetry at very low c
Analytical Biochemistry, 2008
In the study of 1:1 binding, M + X AE MX, isothermal titration calorimetry (ITC) can be used successfully at values of c ≡ K[M] 0 well below the value 1.0 that is often considered its lower limit.