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Updated: Jul 19, 2026

Determining the Thermodynamic and Kinetic Association of a DNA Aptamer and Tetracycline Using Isothermal Titration Calorimetry
Published on: August 23, 2022
Equilibrium and kinetic studies on the interaction of tetracyclines with calcium and magnesium
1Biophysics Division. National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK.
Abstract:
The interaction of Ca2+ and Mg2+ with three Tetracycline antibiotics (tetracycline, chlorotetracycline, and oxytetracycline) has been investigated. Spectrophotometric measurements have been used to determine the apparent association constant for this interaction as a function of pH. It is shown that the results are consistent with a model in which the metal ion can form complexes with both the fully-deprotonated and mono-protonated forms of the Tetracycline. The temperature-jump relaxation method has been used to measure the kinetics of formation of the complexes of Mg2+ with the Tetracyclines. The results are compared with those of previous studies of Mg2+ complex formation reactions and it is shown that the data is consistent with the normal dissociative model. A possible role for metal ion chelation in the mechanism of antibacterial action of the Tetracyclines is discussed.
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