In this paper, we have studied the interaction of CuZnSODⅢand Outer Copper, enzyme activity experiments expressed that 0.1mmol·L-1 Cu2+addition reduced the enzyme activity sharply, but this reduced action had not been found for the additions of 0.1mmol·L-1 1∶1 Cu2+and Zn2+, and 0.1mmol·L-1 Zn2+, respectively. This was due to the Cu2+exchanged the Zn2+in CuZnSODⅢ,and it was proved by the experiment of determination of metal content. Meanwhile, the static fluorescence quenching mechanism revealed the exist of molecular complex of CuZnSOD with Cu2+. The binding constant was obtained from lineweaver burk and double lg plot. The distance of active site to Trp is about 2.83nm, was calculated according to Frster theory.
