Hi, I have an heptamerized antigen of 259 kDa that I cleaved with a protease to induce the exposure of an epitope. However, I want to assess whether this cleavage induced the exposure or induced the release of the epitope from the structure. The MW difference between the intact antigen and the antigen without this portion is 14 kDa. I tried size exclusion chromatography but I couldnt detect this difference in MW. What other techniques could I use: mass spectometry?

Thanks