OpeRATOR, 2000 units


OpeRATOR enzyme for digestion of 2 mg glycoprotein, including one vial of SialEXO for sialic acid removal.

SKU: G2-OP1-020 Category:


Lyophilized OpeRATOR for digestion of 2 mg glycoprotein.
OpeRATOR is an O-glycan specific endoprotease that digests the amino acid backbone N-terminally of the S/T residue.

The enzyme is active on native glycoproteins and does not require denaturing of the glycoprotein. It is active on O-glycan proteins with and without sialic acids, but the activity is higher on proteins where sialic acids have been removed. For this reason, a vial of SialEXO is included. Both OpeRATOR and SialEXO is reconstituted by addition of water.


OpeRATOR is a metalloprotease and as such highly sensitive to chelating agents such as EDTA. Concentrations >5mM lead to complete inhibition of the enzyme. OpeRATOR activity is also moderately inhibited by ZnCl2.

Yes, this workflow enables MS/MS of O-glycosylated peptides with removed O-glycans.

Yes, the enzymes work in combination and can be used to desialylate and digest an O-glycosylated protein.

The relative abundance and site occupancy of O-glycosylation may vary a lot in a glycoprotein sample, and this will result in the generation of peptides with variable sizes. In some cases, the peptides contain more than one O-glycan, i.e. OpeRATOR does not digest at every site in every molecule. However, the missed digestion sites differ from molecule to molecule, and the compiled data will provide valuable information on the O-glycosylated sites.

If digestion is insufficient, it could be caused by the O-glycans having a sterically inaccessible location on the sample that the enzyme cannot reach. In such cases, we recommend trying the following workflow: reduction, denaturation, carboxymethylation, rebuffering, and then digestion with SialEXO and OpeRATOR.

The activity of OpeRATOR is significantly decreased in the presence of sialic acids. We recommend using SialEXO to remove the sialic acids. If this is not an option, then we suggest trying to digest both with and without SialEXO to evaluate the impact for your specific samples and requirements.

No, the enzyme recognizes mucin type glycosylation with an inner GalNAc linked to a hexose sugar.