An Improved Method for the Identification of 4-Hydroxy-2-Nonenal Schiff-Base Adducts Using Data-Dependent and Neutral Loss-Driven MS~(3) Acquisition

摘要

Ten sites susceptible to HNE attack were identified in COX. Compared to conventional data-dependent acquisition, approximately 40percent more of HNE-modified sites were identified by NL-driven MS~(3). Lys in peptides MLD(oxM)KVAPIQGFSAK & KGQDPYNILAPK in COX_(4) and COX_(5)B subunits gave a neutral loss of 138 which improved the identification of Schiff base modified sites with NL-MS~(3). This technique also improved search algorithm scores to acceptable probability thresholds for identification. Since a number of HNE-modified peptides produced a predominant HNE neutral loss fragment-ion signal upon CID, NL-driven MS~(3) data-dependent acquisition was a valuable method to enhance fragmentation information for these particular modified peptides.