Thermodynamics of Mn2+-binding to goat α-lactalbumin

✍ Scribed by J. Desmet; E. Tieghem; H. Dael; E. Cauwelaert

• Book ID: 104778694
• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 542 KB
• Volume: 20
• Category: Article
• ISSN: 1432-1017
• DOI: 10.1007/bf00450561

✦ Synopsis

By means of reaction calorimetry we measured the apparent enthalpy change, delta Happ, of the binding of Mn(2+)-ions to goat alpha-lactalbumin as a function of temperature. The observed delta Happ can be written as the sum of contributions resulting from a conformational and a binding process. In combination with the thermal unfolding curve of goat alpha-lactalbumin, we succeeded in separating the complete set of thermodynamic parameters (delta H, delta G, delta S, delta Cp) into the binding and conformational contributions. By circular dichroism we showed that NH+4-ions, upon binding to bovine alpha-lactalbumin, induce the same conformational change as do Na+ and K+: the binding constant KappNH+4 equals 98 +/- 9 M-1.