Novel Rearrangement of the Sodium Adduct of N-Di-isopropyloxyphosphoryl Dipeptide Methyl Ester in Electrospray Ionization Mass Spectrometry

摘要

Since introduced by Yamashita and Fenn in 1984, electrospray ionization mass spectrometry (ESI-MS) has became a power tool in biological research in recent years. More specifically, ESI-MS has been used in the sequencing of protein and polynucleotide, the elucidation of protein folding path ways, detecting non-covalent complex, quantitative study of enzyme-catalyzed reactions and so on. In the past work of our group, phosphorylated amino acids and peptides have been analyzed by several kinds of mass spectrometer. In our previous report, it was found that a novel rearrangement of the sodium adduct of N-Di-isopropyloxyphosphoryl amino alcohol occurred in the tandem mass of electrospary ionization mass spectrometry (ESI MS/MS) through a penta-coordinate phosphoryl intermediate. Here, we would like to report a strange rearrangement reaction of the [ M + Na ]~+ of N-Di-isopropyloxyphosphoryl dipeptide methyl ester (DIPP-AA-AA-OMe), which has resulted in the same fragment N-mono-isopropyloxyphosphoric acid. It is proved that the oxygen atom in carbonyl group migrated to the phosphoryl group. This is a special reaction, which happen due to the strong electrophilic activity of phosphorous.