Figure 1From: Fluorescent derivatization of a protease antigen to track antigen uptake and processing in human cell linesLC/MS Analysis of FITC-Subtilisin. The de-convoluted mass spectrum shows the un-labeled subtilisin (27,476 Da), subtilisin conjugated to one (27,865 Da) or two (28,255 Da) FITC molecules.Back to article page