کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1196023 | 964444 | 2007 | 7 صفحه PDF | دانلود رایگان |
In peptide sequencing experiments involving a single step tandem mass acquisition, leucine and isoleucine are indistinguishable because both are characterized by a 113 Da mass difference from the other peptide fragments in the MS2 spectrum. In this work, we propose a new method to distinguish between these two amino acids in consecutive MSn experiments, exploiting a gas-phase fragmentation of isoleucine that leads to a diagnostic 69 Da ion. We used this method to assess the Leu/Ile residues of several synthetic peptides. The procedure was then tested on a tryptic digest of myoglobin, assigning the correct amino acid in the majority of the peptides. This work was performed with an old and low-resolution instrument, thus demonstrating that our method is suitable for a wide number of ion trap mass spectrometers, not necessarily expensive or up-to-date.
Journal: Journal of the American Society for Mass Spectrometry - Volume 18, Issue 1, January 2007, Pages 57–63