Journal of the American Society for Mass Spectrometry 2013-02-01

Discrimination of isobaric Leu/Ile residues by MALDI in-source decay mass spectrometry.

Daiki Asakawa, Nicolas Smargiasso, Edwin De Pauw

Index: J. Am. Soc. Mass Spectrom. 24(2) , 297-300, (2013)

Full Text: HTML

Abstract

MALDI in-source decay (ISD) has been used for top-down sequencing of proteins. The use of the matrix 1,5-diaminonapthalene (1,5-DAN) gave abundant w ions, which are formed from the unimolecular dissociation of z• radical fragments via α cleavage reaction and thus help identify which of the isobaric amino acids, Leu or Ile, is present. The high abundance of w ions in MALDI-ISD with 1,5-DAN results from the low collision rate in the MALDI plume. MALDI-ISD with 1,5-DAN appears to be an useful method for the top-down sequencing of proteins, including discrimination of Leu and Ile near the C-terminal end.