Effect of Microenvironment Created by Surfactant on Superoxide Dismutase Activity

Abstract

The activity of SOD (superoxide dismutase) catalyzing dismutation of superoxide radical anion O₂ ⁻ was studied by a modified NBT (nitroblue tetrazolium) method in aqueous solution, micellar solutions and lamellar liquid crystals (LLC) consisting of the surfactants CTAB and TX-100. The experiments showed that the inhibition by SOD of NBT reduction in organized assemblies of surfactants was weaker than in aqueous solution. The order of inhibition was as follows: in phosphate buffer (pH = 7.8) > in TX-100 micelle > in CTAB micelles > in TX-100 LLC > in CTAB LLC. The results were explained by decrease of α-helical content in SOD and difficulty in the transformation of SOD configurations in organized assemblies of surfactant, as well as by catalytic effects of micelles on NBT reduction.

Keywords:

• Lamellar liquid crystal
• Micelle
• SOD activity
• Surfactant

ACKNOWLEDGMENT

The State Key Program Foundation (97021107) and National Natural Science Foundation (29733110) of China supported the work.