Many enzymes are inhibited irreversibly by heavy metal ions such as hg2+ , cu2+ , or ag+ , which can react with essential sulfhydryl groups to form mercaptides. enz−sh+ag+⟶enz−s−ag+h+ the affinity of ag+ for sulfhydryl groups is so great that ag+ can be used to titrate −sh groups quantitatively. to 10.0 ml of a solution containing 3.4 mg/ml of a pure enzyme, an investigator added just enough agno3 to completely inactivate the enzyme. a total of 0.134 μmol agno3 was required. calculate the minimum molecular weight ) of the enzyme.