Program

Poster Presentations

Day 1, May 15（Tue.）　　Poster

1P-01　　PDF

A novel and simple database search strategy to prevent false-positive identification by using a spectral library of unexpected peptides from chemically modified trypsin

(¹Kobe Univ., ²Kobe Univ., ³Matrix Sci., ⁴Kobe Pharm. Univ.)
^oKen-ichi Yoshino^1,2, Itaru Usami³, Atsuko Takeuchi⁴

Chemically modified trypsin by reductive methylation is a standard reagent in protein identification by mass spectrometry. The reductive methylation of trypsin is supposed to protect the enzyme against autolysis. However, it has been reported that peptides with mono- or di-methylated Lys, or Asn residue at their C-termini were observed in autolysis products of chemically modified trypsin. In most cases, the chemical modification of trypsin is not considered in database searches. Modified trypsin-derived spectral data might be incorrectly assigned to peptides of other proteins, making false-positive identification. In this paper, we will present a novel and simple database search strategy to prevent false-positive identification by using a spectral library of unexpected peptides from chemically modified trypsin.