Three lipases targeted using MS
Three lipases were selected as HCP targets for PRM analysis. They are
lipoprotein lipase (LPL), putative phospholipase B-like 2 (PLBL-2), and
lysosomal phospholipase A2 isomer X1 (LPLA2). For each lipase, at least
three unique tryptic peptide sequences were selected for analysis. The
PRM LC-MS instrument setting was similar to the DDA analysis, but the LC
gradient was shortened to 80 min. The MS2 signal responses were analyzed
by Skyline 4.1 software (MacCoss Lab, University of Washington) where
four fragment ions were extracted for each peptide. The PRM
quantification was based on the signal intensities comparison to the
standard lipase proteins.