Does ImpaRATOR cleave at all O-glycosylated sites?
ImpaRATOR has a broad activity towards different O-glycan structures; however, the enzyme has limited activity towards sites with two adjacent O-glycosylated Ser/Thr residues. For complete information about O-glycan sites in glycoprotein substrates containing several sites with two adjacent O-glycosylated Ser/Thr residues, OpeRATOR may be a better option.
Can ImpaRATOR be used under denaturing conditions?
Insufficient digestion during non-denaturing conditions can be caused by O-glycosylation sites within the glycoprotein inaccessible to the enzyme. In such cases, we recommend trying the following workflow: reduction, denaturation, carboxymethylation, buffer-exchange, and then digestion with ImpaRATOR. If detergent is added, make sure to include a detergent removal step prior ImpaRATOR digestion.
Are there any known inhibitors of ImpaRATOR?
ImpaRATOR is a metalloprotease and thereby sensitive to chelating agents such as EDTA. Concentrations > 1 mM EDTA results in complete inhibition of the enzyme. In addition, the ImpaRATOR activity is inhibited by reducing agents and detergents.