Multi-functional MBIT for peptide tandem mass spectrometry.

Area of Science:

• Proteomics
• Analytical Chemistry
• Biochemistry

Background:

• Isobaric tags are crucial for protein identification and quantification in mass spectrometry.
• Existing isobaric tags have limitations in multiplexing and signal detection.

Purpose of the Study:

• To introduce and review the multi-functional capabilities of mass-balanced isotope-coded dipeptide tags (MBITs).
• To highlight MBITs' utility in multiplexed protein quantification and ion temperature measurement.

Main Methods:

• MBITs are based on N-acetyl-Ala-Ala dipeptide with an amine-reactive linker for peptide conjugation.
• MBITs generate distinct low-mass (bS ions) and high-mass (yS ions) quantitation signals.
• Unimolecular dissociation of bS ions yields aS ions, enabling ion temperature measurement.

Main Results:

• MBITs enable 2-plex quantification in the 15-250 fmol range.
• Multiplex quantification is achieved by combining different MBITs.
• MBITs facilitate protein quantification in quadrupole ion trap mass spectrometers using yS ions.
• Concurrent measurement of ion temperature is possible using bS and aS ions.

Conclusions:

• MBITs offer a versatile platform for multiplexed protein quantification in mass spectrometry.
• The unique ability to measure ion temperature enhances the reproducibility of peptide tandem mass spectra acquisition.
• MBITs provide a novel approach for isobaric protein quantification in resonance-type ion traps.