Abstract:

An ion selective electrode of quaternary-ammonium gemini surfactant C12-3-C12·2Br has been fabricated. The variation of electromotive force(EMF) of the systems of C12-3-C12·2Br and bovine serum albumin(BSA) with the concentration of C12-3-C12·2Br has been studied. The binding isotherms and Scatchard plots of the interaction of C12-3-C12·2Br with BSA molecules have been obtained. The numbers of binding sites, Hill coefficient and Hill binding constant have been calculated on the basis of the binding capacity. The results show that the interaction of C12-3-C12·2Br with BSA molecules behaved a positive cooperativity in the binding process. There are two types of binding sites on BSA for C12-3-C12·2Br. One is high-affinity binding site at which the essential role of the interaction is electrostatic force, and the other is low-affinity binding site at which the essential role of interaction is hydrophobic force.

Key words: quaternary-ammonium gemini surfactant, electromotive force, bovine serum albumin, binding isotherm, binding ability