Using Isothermal Titration Calorimetry to Determine Thermodynamic Parameters of Protein–Glycosaminoglycan Interactions
It has now become increasingly clear that a complete atomic description of how biomacromolecules recognize each other requires knowledge not only of the structures of the complexes but also of how kinetics and thermodynamics drive the binding process. In particular, such knowledge is lacking for protein–glycosaminoglycan (GAG) complexes. Isothermal titration calorimetry (ITC) is the only technique that can provide various thermodynamic parameters—enthalpy, entropy, free energy (binding constant), and stoichiometry—from a single experiment. Here we describe different factors that must be taken into consideration in carrying out ITC titrations to obtain meaningful thermodynamic data of protein–GAG interactions.
Key wordsGlycosaminoglycan (GAG) Heparin Free energy Thermodynamics Isothermal titration calorimetry (ITC) Enthalpy Entropy
This work was supported in part by grants P01HL1071521 and R21AI097975 to K.R. and R01GM049760 to J.R. from the National Institutes of Health. The authors would like to thank Dr. Luis Holthauzen for technical support.
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