POSTMan

POSTMan enables targeted fragmentation-based detection and characterization of post-translationally modified peptides often overlooked by collision-induced dissociation (CID) by aligning LC-MS MS(1) data and isolating peptide pairs with user-defined mass differences.

Key Features:

• Targeted Fragmentation: Facilitates targeting of post-translationally modified peptides for fragmentation to improve detection and sequence information recovery.
• Alignment of LC-MS Runs: Aligns liquid chromatography-mass spectrometry (LC-MS) runs both between individual runs and within a single run to support comparative detection of peptide pairs.
• User-Defined Mass Difference Isolation: Isolates peptide pairs that differ by specific mass changes as defined by the user to enable precise identification of modifications.
• MS(1) Data Alignment: Aligns MS(1) signals from LC-MS data to detect peptide pairs with specific mass differences indicative of post-translational modifications.

Scientific Applications:

• Acetylation Analysis: Validated using acetylated peptides to demonstrate capability to assess acetylation modifications.
• Protein Phosphorylation Assessment: Enabled evaluation of basal protein phosphorylation levels, specifically examining phenylalanine hydroxylase (PHA) in intact cells.

Methodology:

The method aligns MS(1) data from LC-MS runs (both between and within runs) to identify peptide pairs with specific, user-defined mass differences indicative of post-translational modifications and focuses on these differential masses to enhance detection sensitivity for modified peptides.