Protease Specificity Profiling in a Pipet Tip Using "Charge-Synchronized" Proteome-Derived Peptide Libraries

Area of Science:

• Biochemistry
• Proteomics
• Enzymology

Background:

• Proteases play crucial roles in biological processes, with ~2% of the genome encoding them.
• Understanding protease specificity is vital for deciphering their functions and developing targeted inhibitors.

Purpose of the Study:

• To present a novel, label-free, proteomics-based method for protease specificity profiling.
• To demonstrate the method's versatility and cost-effectiveness for biochemical laboratories.

Main Methods:

• Utilizes proteome-derived peptide libraries for protease cleavage.
• Employs strong cation exchange chromatography (SCX) in a pipet tip for enrichment of cleaved peptides.
• Label-free analysis requiring simple sample preparation.

Main Results:

• Successfully determined specificity for multiple proteases (GluC, caspase-3, chymotrypsin, MMP-1, cathepsin G) with hundreds to thousands of cleavage events analyzed.
• Discovered a novel preference of cathepsin G for Asn at the P1 subsite, confirmed with synthetic peptides.

Conclusions:

• The developed method is straightforward, cost-effective, and requires minimal equipment.
• This approach can be widely adopted in biochemistry labs to enhance understanding of protease specificity.