Thermodynamics of the binding of calcium and strontium to bovine α‐lactalbumin

FEBS Letters

Milos, Mladen¹  Cox, Jos A.²  Schaer, Jean-Jacques¹ 

[1] Department of Physical Chemistry, University of Geneva, 30, quai Ernest-Ansermet. 1211 Geneva 4, Switzerland;Department of Biochemistry, University of Geneva, 30, quai Ernest-Ansermet. 1211 Geneva 4, Switzerland

关键词: Microcalorimetry;    α-Lactalbumin;    Ca2+ binding;    Sr2+ binding;   

DOI  :  10.1016/0014-5793(85)80431-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Microcalorimetry and equilibrium gel filtration were used to determine the thermodynamic functions ΔH°, ΔG° and ΔS° guiding the interaction of Ca²⁺ and Sr²⁺ with bovine α-lactalbumin. Two methods of nearly complete metal removal from the protein gave identical results. The single Ca- and Sr-binding site, which has moderate affinity for these ions (K _ca = 2.5 × 10⁶ M⁻¹ and K _Sr = 5.1 × 10⁵ M⁻¹), displays unusually large enthalpy changes of −118 kJ · mol⁻¹ for Ca²⁺ and −75 kJ·mol⁻¹ for Sr²⁺. The concomitant reaction entropies equal −273 and −142 J·K⁻¹· mol⁻¹, respectively.

【 授权许可】

Unknown