Parallel Reaction Monitoring (PRM) is an ion monitoring technique based on high-resolution and high-precision mass spectrometry. The principle of PRM is similar to that of SRM/MRM, but PRM is more commonly used for absolute quantification of proteins and peptides in the development of analytical methods. PRM technology can detect multiple proteins at the attomole level in complex samples.
Parallel Reaction Monitoring (PRM)
PRM is a quadrupole high-resolution mass spectrometry detection platform based on Q-Orbitrap. Unlike SRM, which performs one transition at a time, PRM executes a full scan through precursor ions for each transition, meaning it simultaneously monitors all fragments of the precursor ion: firstly, PRM uses a quadrupole (Q1) to select precursor ions, generally selecting a range of m/z ≤ 2; then, the precursor ions are fragmented in a collision cell (Q2); finally, Orbitrap replaces Q3, scanning all fragmented ions with high resolution and precision. Therefore, PRM technology not only has the quantitative analysis capability of SRM/MRM targets but also has qualitative capabilities.
Advantages of PRM
1. Mass accuracy can reach ppm levels, better eliminating background interference and false positives compared to SRM/MRM, effectively improving detection limits and sensitivity in complex backgrounds;
2. Full scan of product ions without the need to select ion pairs, making it easier to develop analytical methods;
3. A wider linear range: increased to 5-6 orders of magnitude.
Advantages of SRM/MRM technology
• High sensitivity;
• High throughput;
• Easier to develop analytical methods.
Main Process of Parallel Reaction Monitoring PRM Analysis by Biotage Biotech:
1. PRM Method Development: First, select 2 or 3 targeted peptides from a mass spectrometry library or Skyline software. The selected peptides should be unique to the target protein, easily detectable by LC-MS, without missing cleavage sites and with minimal post-translational modifications. Next, establish a standard curve based on the x-axis as concentration ratio and y-axis as peak area ratio.
2. Mass Spectrometry Analysis: Analyze the hydrolyzed samples using Thermo's latest Obitrap Fusion Lumos mass spectrometer.
3. Data Analysis: Use Skyline software for data analysis.
Applications of PRM
• Verification of differential proteins in iTRAQ;
• Verification of label-free differential proteins;
• Absolute quantification of peptides and proteins;
• Quantification of disease markers and establishment of diagnostic models;
• Quantification of phosphorylated and methylated proteins;
• Quantification of other post-translationally modified proteins;
• Quantitative analysis of metabolic pathways.
