Interaction between sodium n-undecyl sulfate and insulin.
The binding of sodium n-undecyl sulfate with bovine insulin was studied at pH 3.2 and 10 by equilibrium dialysis at 25 degrees C. The binding data have been used to determine the Gibbs energies of interaction using the theoretical model of the Wyman binding potential. The curves of Gibbs energies as a function of the number of bound ligands (v) tend to limiting values of around -14 kJ mol-1 at high values of v. The enthalpies of interaction have been measured directly by microcalorimetry showing an increase of exothermicity at lower pH. The results have been compared with similar data for the interaction of anionic surfactants with insulin.
Prieto
G
G
Departamento de Físcia Aplicada, Facultad de Física, Universidad de Santiago de Compostela, Spain.
del Rio
J M
JM
Paz Andrade
M I
MI
Sarmiento
F
F
Jones
M N
MN
D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000378:metabolism*; D013463:Sulfuric Acid Esters / Q000378:metabolism*; D013816:Thermodynamics
D007328:Insulin; D013463:Sulfuric Acid Esters; C086030:undecyl sulfate