Maximizing Cumulative Trypsin Activity with Calcium at Elevated Temperature for Enhanced Bottom-Up Proteome Analysis.

Area of Science:

• Proteomics
• Biochemistry

Background:

• Bottom-up proteomics requires efficient trypsin digestion for mass spectrometry (MS) analysis.
• Elevated temperatures can accelerate proteolysis but may degrade trypsin, limiting enzyme activity over time.

Purpose of the Study:

• To quantify calcium-stabilized trypsin activity over time at elevated temperatures.
• To optimize trypsin digestion for enhanced peptide identification and digestion efficiency in bottom-up proteomics.

Main Methods:

• Spectroscopic (BAEE) assay to measure trypsin activity and stability.
• Bottom-up MS analysis of yeast proteome extract.
• Optimization of digestion temperature and calcium concentration.

Main Results:

• Calcium addition at 47°C enhances trypsin stability 25-fold, increasing cumulative activity compared to higher temperatures.
• A 1-hour digestion at 47°C with 10 mM Ca2+ yielded a 29% increase in peptide identifications.
• This protocol reduced missed cleavage sites and improved trypsin specificity, decreasing semi-tryptic peptides.

Conclusions:

• Optimized trypsin digestion at 47°C with calcium enhances throughput and efficiency for bottom-up proteomics.
• This method offers a robust and cost-effective alternative for maximizing protein digestion.
• The findings validate a protocol for improved peptide identification and digestion quality.