One-step procedure for peptide extraction from in-gel digestion sample for mass spectrometric analysis

Protein identification from samples resolved by one-dimensional and two-dimensional gel electrophoresis is highly dependent on the recovery of trypsin-digested peptides prior to mass spectrometric analysis. The commonly used two-step protocol for extracting tryptic peptides, involving high-volume organic solvent extraction and cleanup via microscale reversed-phase micropipet tip or microcolumn is not only limited by significant sample loss but is also costly and very labor-intensive. We report here a simple one-step procedure for simultaneous peptide extraction and cleanup by incubating a small piece of C18 Empore Disk (3M) with the in-gel digested solution. We show that the direct Empore Disk-based peptide extraction procedure is convenient, economical, and has higher efficiency as compared with the commonly used two-step protocol for peptide preparation prior to MS analysis.