Enhanced Ionization of Phosphopeptide Using Ammonium Phosphate as Matrix Additive by MALDI-MS

Enhanced Ionization of Phosphopeptide Using Ammonium Phosphate as Matrix Additive by

MALDI-MS

ZHANG,Ying;LU,Hao-Jie;YANG,Peng-Yuan

【期刊名称】《中国化学（英文版）》 【年(卷),期】2008(026)010

【摘要】A new method based upon adding ammonium phosphate as a matrix additive to enhance the ionization efficiency of phosphopeptide in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was described. Furthermore, influences of different phosphate salts at various concentrations on the ionization efficiency of phosphopeptide were investigated systematically, finding that the signal intensity for phosphopeptide 48FQ[pS]EEQQQTEDELQDK63 digested from β-casein were 5 to 8 times increased in an optimized condition with 10 mmol/L ammonium monobasic phosphate or 3 to 4 times increased with 10 mmol/L ammonium dibasic phosphate as additive to matrix 2,5-dihydroxybenzoic acid, respectively. Compared with the most optimized matrix system that was currently reported for special ionization

of

phosphopeptides,

the

signal

intensity

of

this

phosphopeptide was also enhanced by twice when introducing 5 mmol/L

ammonium

dibasic

phosphate

into

matrix

2,4,6-

trihydroxyacetophenone. In addition, the mechanism was also discussed,