“…5B and C, predominant mass peaks at m/z 430.20 and m/z 231.20, as well as their ion peaks, were analyzed by manual calculation to be Asn-Thr-Val-Pro (NTVP) and Ile-Val (IV) or Leu-Val (LV). According to the principle of various classical types of amino acid fragments, a-ion, b-ion, c-ion, x-ion, y-ion and z-ion, which have unique weights depending on their components, are detected by the following criteria: a-ions, molecular mass of amino acid residue plus 27; b-ions, plus 1; c-ions, plus 18; x-ions, plus 45; y-ions, plus 19; and z-ions, plus 2 (Bruni, Gianfranceschi, & Koch, 2005;Li et al, 2007) Nevertheless, the peptide sequence at m/z 231.20 (Fig. 5C) should be confirmed, because I (Ile) and L (Leu) have the same molecular weight of 131.…”