Ously(13). Peptides were analyzed using a linear ion trap (LTQ) mass spectrometer (Thermo Fisher Scientific) in positive ion mode. An in-house software package, RAWDistiller v. 1.0, was used to convert the resulting .raw files to .ms2 files. MS/MS spectra were then matched to 29,375 human protein sequences (National Center of Biotechnology Information, November 2010 release) using the SEQUEST algo