Does the enzyme require the sample to be in the native fold or would denaturation help?

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.