1P-27 PDF
3H4NBAを用いたMALDI In-Source Decay
In-source decay (ISD) in matrix-assisted laser desorption/ionization (MALDI) is a rapid sequencing method for peptides.1,5-Diaminonaphthalene (1,5-DAN) is a most frequently used matrix for ISD. However, the use of 1,5-DAN generates mainly c-series ions, which is difficult to distinguish leucine (Leu) and isoleucine (Ile), and lacks at the left side of Pro. Several oxidizing matrices generating a- and d-series ions has been reported, but remained an issue for the sensitivity. 3-Hydroxy-4-nitrobenzoic acid (3H4NBA) had been reported as a matrix for 2-nitrobenzensulfenyl (NBS)-labeled peptides (Proteomics, 2006, 6, 2042-2049). Herein, we used 3H4NBA for ISD.
A lot of a- and d-series ions for amyloid β 1-40 were detected with high sensitivity using 3H4NBA. All the two Leu and two Ile were identified by the d-series ions. The ions were detected over the entire area of the matrix-analyte spot. The same tendency was observed for N-acetyl renin substrate and ACTH 18-39. The a-series ions were detected even at the left side of Pro. Sensitivity of the a-series ions using 3H4NBA was a little lower than c-series ions using 1,5-DAN, and higher than using oxidizing matrices such as 5-formyl salycilic acid and 5-nitrosalycilic acid. It was confirmed that 3H4NBA was a useful oxidizing matrix for ISD.