“P3” Sample Prep in the ProTrap XG: Precipitate, Purify, & Pepsin Digestion

Kate Lynn C.P. Smith, Alan A. Doucette
Department of Chemistry, Dalhousie University Halifax, Nova Scotia, Canada

Introduction

Though trypsin is favored for bottom up proteomics workflows, alternative coverage, or in instances where basic digestion conditions are not possible eg. HDX) Pepsin digestion is conventionally performed in dilute HCl to mimic the natural low pH environment of the stomach In prior work, we showed that formic acid is ideally suited to resolubilize precipitated proteins, being recommended for top down proteomic workflows. Here, we establish a complete proteomics workflow within a single spin cartridge device known as the ProTrap XG Proteins can be extracted from cells, purified by precipitation, resolubilized in concentrated formic acid, digested with pepsin, and subject to further fractionation, all within the device, ahead of MS.