Figure 9. MALDI-TOF profile of 9 kDa isoform I

The MALDI-TOF profiles of the 9 kDa isoform II and III were similar to the profile 9 kDa isoform I. Note that among the four expected tryptic fragments of 9 kDa polypeptide at the C-terminal regions (fragments RYQDWGATNAR [residues 153-163, mass 1,337], YQDWGATNAR [residues 154-163, mass 1,181], YQDWGATNARVGSLR [residues 154-168, mass 1,693], and VGSLRRVIDFS [residues 164-174, mass 1,248]), the tryptic fragments with mass of 1181 and 1337 were present but tryptic fragments with mass of 1248 and 1693 were absent. The results suggested that the tryptic fragment after residue number 163 was absent in the 9 kDa isoforms.