Abstract
By means of reaction calorimetry we measured the apparent enthalpy change, ΔHapp, of the binding of Mn2+-ions to goat α-lactalbumin as a function of temperature. The observed ΔHapp 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 α-lactalbumin, we succeeded in separating the complete set of thermodynamic parameters (ΔH, ΔG, ΔS, ΔCp) into the binding and conformational contributions. By circular dichroism we showed that NH +4 -ions, upon binding to bovine a-lactalbumin, induce the same conformational change as do Na+ and K+: the binding constant \(K_{NH_4^ + }^{app} \) equals 98 ± 9 M−1.
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Abbreviations
- BLA:
-
bovine α-lactalbumin
- GLA:
-
goat α-lactalbumin
- HLA:
-
human α-lactalbumin
- CD:
-
circular dichroism
References
Bevington P (1969) Data reduction and error analysis for the physical sciences. McGraw-Hill, New York
Desmet J, Van Cauwelaert F (1988) Calorimetric experiments on Mn2+-binding to α-lactalbumin. Biochim Biophys Acta 957:411–419
Desmet J, Hanssens I, Van Cauwelaert F (1987) Comparison of the binding of Na+ and Ca2+ to Bovine α-lactalbumin. Biochim Biophys Acta 912:211–219
Desmet J, Van Dael H, Van Cauwelaert F, Nitta K, Sugai S (1989) Comparison of the binding of Ca2+ and Mn2+ to bovine α-lactalbumin and equine lysozyme. J Inorg Biochem 37:185–191
Gerken TA (1984) Amino group environments and metal binding properties of carbon-13 reductively methylated alpha-lactalbumin. Biochemistry 23:4688–4689
Hiraoka Y, Sugai S (1984) Thermodynamics of thermal unfolding of bovine apo-α-lactalbumin. Int J Pept Prot Res 23:535–542
Hiraoka Y, Sugai S (1985) Equilibrium and kinetic study of sodium-and potassium-induced conformational changes of apo-α-lactalbumin. Int J Pept Prot Res 26:252–261
Kronman MJ (1989) Metal-ion binding and the molecular conformational properties of α-lactalbumin. Crit Rev Biochem Mol Biol 24:565–668
Kuroki R, Taniyama Y, Seko C, Nakamura H, Kikuchi M, Ikahara M (1989) Design and creation of a Ca2+ binding site in human lysozyme to enhance structural stability. Proc Natl Acad Sci USA 86: 6903–6907
Kuwajima K, Harushima Y, Sugai S (1986) Influence of Ca2+ binding on the structure and stability of bovine α-lactalbumin studied by circular dichroism and nuclear magnetic resonance spectr. Int J Pept Prot Res 27:18–27
Lindahl L, Vogel HJ (1984) Metal-ion dependent hydrophobic-interaction chromatography of α-lactalbumins. Anal Biochem 140:394–402
Martell AE, Smith RM (eds) (1974) Critical stability constants: amino acids, vol 1. Plenum Press, New York, p 204
Murakami K, Andree PJ, Berliner LJ (1982) Metal ion binding to alpha-lactalbumin species. Biochemistry 21:5488–5494
Pfeil W (1981) Thermodynamics of α-lactalbumin unfolding. Biophys Chem 13:181–186
Segawa T, Sugai S (1983) Interactions of divalent metal ions with bovine, human and goat α-lactalbumin. J Biochem (Tokyo) 93:1321–1328
Stuart DI, Acharya KR, Walker NPC, Smith SG, Lewis M, Phillips DC (1986) α-Lactalbumin possesses a novel calcium binding loop. Nature 324:84–87
Van Ceunebroeck J Cl, Hanssens I, Joniau M, Van Cauwelaert F (1985) Thermodynamics of the Ca+ binding to bovine α-lactalbumin. J Biol Chem 260:10944–10948
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Desmet, J., Tieghem, E., Van Dael, H. et al. Thermodynamics of Mn2+-binding to goat α-lactalbumin. Eur Biophys J 20, 263–268 (1991). https://doi.org/10.1007/BF00450561
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DOI: https://doi.org/10.1007/BF00450561