The immunoglobulin-degrading enzyme from Streptococcus pyogenes (IdeS) is a highly specific protease that cleaves Immunoglobulin G (IgG) at a single site below the hinge region, yielding F(ab’)2 and Fc fragments (Figure 1).   
   
The IdeS Protease can be used to characterize therapeutic antibody candidates using LC/MS. The Promega IdeS Protease is a recombinant, engineered version of the enzyme from S. pyogenes and contains a histidine tag for easy removal.