Figure 6: MALDI ToF MS peptide mapping analysis and amino acid sequence of RA33. [A] Mass spectrum range m/z 1100–1500 shows RA33 epitope peptide in early eluting fraction (fraction 3) upon incubation with anti-RA33 mAb. [B] Mass spectrum of late eluting fraction (fraction 8) RA33 peptides in the absence of anti-RA33 mAb. [C] Mass spectrum of thermolytic RA33 peptides. [D] Amino acid sequence in single letter code of RA33 showing sequence coverage after thermolysin digest in bold letters. The shaded sequence displays the epitope motif that is recognized by the anti-RA33 mAb. Matrix: DHB, E: derived from thermolysin autoproteolysis, Δ: potassium adduct, B: derived from buffer, *: oxidation.