Biophysical journal
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Biophysical journal · Apr 1997
Titration calorimetry of anesthetic-protein interaction: negative enthalpy of binding and anesthetic potency.
Anesthetic potency increases at lower temperatures. In contrast, the transfer enthalpy of volatile anesthetics from water to macromolecules is usually positive. The transfer decreases at lower temperature. ⋯ The low-affinity K was 189 +/- 3.8 M-1 (KD = 5.29 mM), with a Bmax of 13.2 +/- 0.3. Anesthetic potency is a function of the activity of anesthetic molecules, not the concentration. Because the sign of delta H determines the temperature dependence of distribution of anesthetic molecules, it is irrelevant to the temperature dependence of anesthetic potency.