Identification of naturally citrullinated CXCL10. Natural CXCL10 was subjected to Edman degradation. Overlays are shown of the RP-HPLC chromatograms detected at 270 nm (mAU, milliabsorption units) of 2 pmol of the 19 PTH amino acids (indicated by their 1-letter code on the top chromatograms) and of the 5th amino acid in the CXCL10 sequence (A) or of PTH-citrulline (Cit; B). ↙ indicates the major signal in these chromatograms.