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

Cu(II) - salicylate complex has been synthesized and its crystal structure has been determined. The activity of SOD and Cu (II) - complex catalyzing d ismutation of superoxide radical (O-2(-.)) has been studied by improved NBT method in phosphate buffer (pH = 7.8), micellar solution and lamellar liqu id crystals (LLC) formed fi-om surfactants CTAB or TX - 100. The X - my dif fraction indicates that the Cu(II) - complex has a formula Cu-2 (HSal)(4)Et OH .H2O and similar structure to SOD active site. It was proposed from EPR spectra that the reaction mechanism of Cu(II) complex catalyzing O-2(-.) di smutation was similar to that of the proposed dismutation reaction catalyze d by SOD. The results obtained by improved NBT method show the inhibition b y SOD or Cu(II) - salicylate complex of NBT reduction in organized assembli es of surfactants is weaker than in aqueous solution. The order of inhibiti on is as follows: in phosphate buffer > in CTAB micelle > in CTAB lamellar liquid crystal; in nonionic TX - 100 organized assemblies > in cationic CTA B organized assemblies. The results can be explained by catalytic effect of micelle, high viscosity of LLC and decrease of a - helical content in SOD in organized assembly of surfactants. The effect of PrCl3 on SOD - like activity of Cu (II) - complex in phosphat e buffer (pH = 7.8) has been determined. The results indicate that PrCl3 ca n inhibit the reduction of NBT by itself. The cooperativity of PrCl3 and Cu (II) - complex has been also obtained, however, the reaction mechanism of P rCl3 is different from that of SOD and Cu(II) - complex.