Conditions for calibration of an isothermal titration calorimeter using chemical reactions

Abstract

The reaction of protonation of 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) is a suitable one for the calibration of isothermal titration calorimeter (ITC), providing that experimental conditions are appropriately chosen. The conditions and methods for handling experimental data from a nanowatt-ITC are discussed. Also, the binding of Ba(2+) to 18-Crown-6 is successfully used to check the accuracy and precision of the chemical calibration performed with TRIS. This latter reaction has the additional advantage that the data can also be used for a check on the determination of the value of a binding constant. The anomaly of the first injection in ITC is analyzed and, by combining calorimetric and spectroscopic measurements, it is shown that it mainly results from a backlash effect of the syringe plunger rather than from a diffusion effect.

Anion Encapsulation Drives the Formation of Dimeric GdIII[15-metallacrown-5]3+ Complexes in Aqueous Solution

“…Because the calorimetric technique has been proven to be a straightforward, convenient, and accurate method for assessing the stoichiometries and binding affinities of different guests with several hosts 8d,11,12 the interaction of MC with guests 1–6 in water was probed using isothermal titration calorimetry (ITC). 13,14 An example of typical experimental results is shown in Figure 1.…”

Fast and accurate enzyme activity measurements using a chip-based microfluidic calorimeter

“…the rate of heat (J/s) produced or consumed by a reaction, we need to know the effective sensitivity S TP (V/W) of each thermopile. To determine the effective sensitivity of each thermopile we used the Tris-HCl reaction, which has been widely applied for calibration of calorimeters [22,23]. Different amounts of HCl were mixed with 200 mM Tris, and the output of each thermopile, which is in μV as a function of time, was obtained after correction for the blank heat (Fig.…”

Ubiquitin Associates with the N‐Terminal Domain of Nerve Growth Factor: The Role of Copper(II) Ions

“…[28] In at ypical peptide/protein binding experiment, the peptide solution was injected in 29 aliquots of 7.98 mL( except the first injection, which was 2 mL) into a950 mLs ample cell containing Ub. The calorimeter was routinely calibrated by titrating a1m m solution of HCl into 30 mm TRIS buffer,a sr eported elsewhere.…”

“…The calorimeter was routinely calibrated by titrating a1m m solution of HCl into 30 mm TRIS buffer,a sr eported elsewhere. [28] In at ypical peptide/protein binding experiment, the peptide solution was injected in 29 aliquots of 7.98 mL( except the first injection, which was 2 mL) into a950 mLs ample cell containing Ub. The heats of dilution were determined in as eparate experiment by titrating peptide solutions into the buffer.C alorimetric data were analyzed by using the NanoAnalyze software (TAI nstruments, New Castle, USA) to obtain the gross heat evolved/absorbed in the reaction.…”