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Thermodynamic and kinetic analyses of curcumin and bovine serum albumin binding

Hudson, Eliara Acipreste, de Paula, Hauster Maximiler Campos, Ferreira, Guilherme Max Dias, Ferreira, Gabriel Max Dias, Hespanhol, Maria do Carmo, da Silva, Luis Henrique Mendes, Pires, Ana Clarissa dos S.
Food chemistry 2018 v.242 pp. 505-512
bovine serum albumin, calorimetry, curcumin, digitoxin, dimethyl sulfoxide, enthalpy, fluorescence, ibuprofen, photolysis, stoichiometry, surface plasmon resonance, warfarin
Bovine serum albumin (BSA)/curcumin binding and dye photodegradation stability were evaluated. BSA/curcumin complex showed 1:1 stoichiometry, but the thermodynamic binding parameters depended on the technique used and BSA conformation. The binding constant was of the order of 105L·mol−1 by fluorescence and microcalorimetric, and 103 and 104L·mol−1 by surface plasmon resonance (steady-state equilibrium and kinetic experiments, respectively). For native BSA/curcumin, fluorescence indicated an enthalpic and entropic driven process based on the standard enthalpy change (ΔH○F=−8.67kJ·mol−1), while microcalorimetry showed an entropic driven binding process (ΔH○cal=29.11kJ·mol−1). For the unfolded BSA/curcumin complex, it was found thatp ΔH○F=−16.12kJ·mol−1 and ΔH○cal=−42.63kJ·mol−1. BSA (mainly native) increased the curcumin photodegradation stability. This work proved the importance of using different techniques to characterize the protein-ligand binding.