A Sulfoxide-Based Isobaric Labelling Reagent for Accurate Quantitative Mass Spectrometry

Area of Science:

• Proteomics
• Analytical Chemistry
• Mass Spectrometry

Background:

• Accurate peptide quantification is crucial for modern proteomics.
• Isobaric tags are commonly used for relative quantification, enabling multiplexed sample analysis.
• Existing isobaric tags rely on gas-phase separation of balancer and reporter elements.

Purpose of the Study:

• To develop a novel isobaric labeling reagent with improved fragmentation characteristics.
• To enhance the sensitivity and accuracy of relative peptide quantification in complex mixtures.
• To enable more robust complementary ion analysis in mass spectrometry.

Main Methods:

• Design and synthesis of a new isobaric labeling reagent featuring a sulfoxide linkage.
• Utilizing sulfoxide pyrolysis for controlled and asymmetric cleavage.
• Employing mass spectrometry for fragmentation analysis and signal detection.

Main Results:

• The new reagent demonstrates significantly improved fragmentation compared to existing methods.
• Enhanced intensity of complementary ion signals was observed.
• The reagent facilitates easier and asymmetric cleavage at low fragmentation energy.
• The findings support complementary ion cluster analysis for improved quantification.

Conclusions:

• The novel sulfoxide-linked isobaric tag offers superior fragmentation efficiency for proteomics.
• This advancement improves the accuracy and sensitivity of relative peptide quantification.
• The reagent design facilitates more reliable complementary ion analysis in mass spectrometry.