Novel synthetic method of phosphonamidate peptides and its application in peptide sequencing via multistage mass spectrometry

Abstract

Phosphonamidate peptides were prepared in good yields by reaction of ethoxy(phenyl)phosphinate with free peptides in a mixed solution of H₂O, C₂H₅OH, Et₃N and CCl₄ at room temp.; their in situ electrospray ionization mass spectra exhibited high sensitivity compared with the free peptides, and sequential loss of amino acid residues of the sodiated phosphonamidate peptides from the C-terminus was found in multistage ESI mass spectrometry. The results show that N-phosphonyl derivatization combined with multistage ESI-MS is a powerful method for peptide sequencing.