Sensitive Identification of Phosphopeptides in Brain Tissue using 2D-NanoLC-ESI-MSⁿ

Introduction

One of the most important post-translational modifications is phosphorylation of serine, threonine or tyrosine residues. Detection of phosphorylation sites by mass spectrometry in proteins extracted from biological material is complicated by low abundance, low stoichiometry, and poor ionization of phosphopeptides [1].

In this work, a biocompatible nano liquid chromatography (LC) system, Ettan™ MDLC, was used for separating tryptic peptides from brain tissue by cation exchange (SCX) to enrich the phosphopeptides followed by reversed-phase chromatography (RPC). The phosphopeptides were detected by neutral loss MS.