Microfabrication-based isothermal titration calorimetry using a combined in-mixing and post-mixing titration approach

2018 ◽  
Vol 10 (38) ◽  
pp. 4665-4670 ◽  
Author(s):  
Xiangsong Feng ◽  
Yuan Jia ◽  
Hongyuan Jiang ◽  
Qiao Lin
Keyword(s):  
Thermodynamic Parameters ◽  
Isothermal Titration Calorimetry ◽  
Accurate Determination ◽  
Titration Calorimetry ◽  
Reaction Systems ◽  
Microfabrication Technology

Advances in microfabrication technology can enable innovative tools for isothermal titration calorimetry (ITC) with a combined in-mixing and post-mixing titration, for accurate determination of thermodynamic parameters of reaction systems.

Stirring rate affects thermodynamics and unfolding kinetics in isothermal titration calorimetry

2020 ◽  
Vol 168 (1) ◽  
pp. 53-62
Author(s):  
Takahiro Maruno ◽  
Tadayasu Ohkubo ◽  
Susumu Uchiyama
Keyword(s):  
Thermodynamic Parameters ◽  
Isothermal Titration Calorimetry ◽  
Titration Calorimetry ◽  
Reaction Heat ◽  
Ligand Interaction ◽  
New Approach ◽  
Stirring Rate ◽  
Protein Ligand Interaction ◽  
Unfolding Kinetics

Abstract Isothermal titration calorimetry (ITC) directly provides thermodynamic parameters depicting the energetics of intermolecular interactions in solution. During ITC experiments, a titration syringe with a paddle is continuously rotating to promote a homogeneous mixing. Here, we clarified that the shape of the paddles (flat, corkscrew and small-pitched corkscrew) and the stirring rates influence on the thermodynamic parameters of protein–ligand interaction. Stirring with the flat paddle at lower and higher rate both yielded a lower exothermic heat due to different reasons. The complete reaction with no incompetent fractions was achieved only when the stirring was performed at 500 or 750 rpm using the small-pitched corkscrew paddle. The evaluation of the protein solution after 1,500 rpm stirring indicated that proteins in the soluble fraction decreased to 94% of the initial amount, among which 6% was at an unfolded state. In addition, a significant increase of micron aggregates was confirmed. Furthermore, a new approach for the determination of the unfolding kinetics based on the time dependence of the total reaction heat was developed. This study demonstrates that a proper stirring rate and paddle shape are essential for the reliable estimation of thermodynamic parameters in ITC experiments.

scholarly journals Calorimetric techniques applied to the thermodynamic study of interactions between proteins and polysaccharides

2016 ◽  
Vol 46 (8) ◽  
pp. 1491-1497
Author(s):  
Monique Barreto Santos ◽  
Bernardo de Sá Costa ◽  
Edwin Elard Garcia Rojas
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermodynamic Parameters ◽  
Isothermal Titration Calorimetry ◽  
Thermal Energy ◽  
Titration Calorimetry ◽  
Biological Macromolecules ◽  
Valuable Insight ◽  
Scanning Calorimetry ◽  
Temperature Scanning ◽  
Insight Into

ABSTRACT: The interactions between biological macromolecules have been important for biotechnology, but further understanding is needed to maximize the utility of these interactions. Calorimetric techniques provide information regarding these interactions through the thermal energy that is produced or consumed during interactions. Notable techniques include differential scanning calorimetry, which generates a thermodynamic profile from temperature scanning, and isothermal titration calorimetry that provide the thermodynamic parameters directly related to the interaction. This review described how calorimetric techniques can be used to study interactions between proteins and polysaccharides, and provided valuable insight into the thermodynamics of their interaction.

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