Patent ID: 8647880

Claim:
A method of detection of an amino acid sequence for identification of peptides and/or proteins, the method comprising the following steps: selective derivatization of an N-terminus of a peptide or an N-terminus of a protein having an unprotected ε-amine of lysine versus derivatization of the unprotected ε-amine of lysine, wherein the selective derivatization is carried out at pH 1-5 with addition of sodium cyanoborohydride (NaBH 3 CN) using a derivatization compound, the derivatization compound comprising an aldehyde group as a reactive group and two or more sulfonic acid groups, wherein the selective derivatization comprises reacting of the aldehyde group with an amino group at the N-terminus of the peptide and/or at the N-terminus of the protein to form derivatized analytes in a form of a secondary amine; mass spectrometer analysis of the derivatized analytes by acquiring spectra of derivatized negative ions in a negative mode of operation of a mass spectrometer; determining an amino acid sequence of the derivatized analytes by interpretation of fragmentation sequence data obtained from the mass spectrometer analysis.