The fruit of has a lot of acidic proteases and its extract has been used in cheese manufacturing. However, there are few studies about purification and characterization of this enzyme. must be satisfied for the enzyme to be used in industry: 1- stability of enzymes against metal ions and 2- Ability to sustain proper function and stability in the absence of metal ion. Accordingly, in this investigation, the effect of various ions different concentrations activity, stability and somewhat on structural properties of the purified protease were studied. Based on the results, it was shown that the enzyme was relatively stable against NaCl and CaCl₂, but by increment of these salts, stability and activity of enzyme . Also, the enzyme was stable against low concentration of various metal ions and only Hg²⁺ reduces enzyme stability and activity. By studying the role of ²⁺ of , it was found that ²⁺ have any role in thermal stability of enzyme at 67˚C. Likewise, by observing the effect of metal ions on of it was that all tested ions increased intensity of emission and caused to shift toward lower wave length. In all, of these showed that the purified enzyme from bad is very stable against various metal heavy metals and it is favorable for industrial application.