日本質量分析学会 第66回質量分析総合討論会

Program

Poster Presentations

Day 2, May 16(Wed.)  Poster

Oxidative radical driven cleavage of peptides with MALDI-ISD

(Yokohama City Univ.)
oMariko Yamakoshi, Mitsuo Takayama

Although MALDI-ISD of peptides and proteins results in c-ions originating from cleavage at the N-Cα bond of backbone, we recently found that (a + 16)- and y-ions caused by oxidative radical driven cleavage are formed by low matrix/analyte ratios (M/A). Here we performed MALDI-ISD experiments with various matrices to determine the source of reactive oxygens using a peptide ACTH 18-39. Oxidative degradation products (a + 16)- and y-ions were observed when the molar ratio M/A was extremely small. Laser desorption ionization experiments of peptides without any matrix did not give any oxidative degradation products, but specific cleavage was observed depending on the amino acid sequence.