In this paper, a method of microdialysis coupled with high performance liquid chromatography (HPLC) was established to study the quantitative interaction of superoxide dismutase (Cu_2Zn_2SOD) with histidine and histidine-metal ion complexes. It was observed that not only histidine, but also histidine-Co(II) and histidine-Ni(II) could induce and substitute some Cu(II) and Zn(II) from Cu_2Zn_2SOD, eventually influence the activity of this metalloenzyme. Histidine- metal ion complexes have stronger ability than histidine to displace the bound metal ion from SOD. In addition, the amount of foreign metal ion binding to the SOD was less than that of metal ion lost from SOD. It obviously means that there was apoenzyme in the solution.

Key words: METAL, ENZYME, MOLECULAR, SOLID COMPLEX, SUPEROXIDE DISMUTASE, INTERACTIONS, HIGH-SPEED LIQUID CHROMATOGRAPHY