Effect of surfactant microenvironment on SOD-like activity of Cu(II)-salicylate complex

Cu(II)-salicylate was synthesized and characterized by X-ray diffraction. T he reaction mechanism of the Cu(II) complex with superoxide anion was studi ed by ESR spectroscopy, and its (superoxide dismutase) SOD-like activity wa s determined by a modified illumination method in phosphate buffer (pH = 7. 8), micelle solutions and lamellar liquid crystals formed from surfactants CTAB and TX-100. X-ray diffraction indicated that the Cu(II) complex had a formula Cu-2(Hsal)(4)EtOHH2O and a similar structure to the SOD active site . EPR spectra proved that the reaction mechanism of the Cu(II) complex cata lyzing O-2(-) dismutation was the same as that of the proposed dismutation reaction catalyzed by SOD. Results obtained by the NBT method indicated tha t the Cu(II)-complex showed SOD-like activity, and the effect of microenvir onment created by surfactants on its activity was same as on SOD activity. The order of the inhibition of NBT reduction by the Cu(II)-complex in diffe rent microenvironments was: in phosphate buffer (pH = 7.8) > in TX-100 mice lle > in TX-100 liquid crystal, and in nonionic TX-100 organized assemblies > in cationic CTAB organized assemblies. These results Were explained by t he catalytic effect of micelles, and by the space restriction and high visc osity of organized assemblies of surfactants.