Beta galactosidase enzyme fragment complementation as a high-throughput screening protease technology.

Area of Science:

• Biochemistry
• Assay Development
• Enzymology

Background:

• Protease activity is crucial in biological processes and disease.
• High-throughput screening (HTS) assays are vital for identifying protease inhibitors.
• Existing assays may lack sensitivity or flexibility for diverse protease targets.

Purpose of the Study:

• To develop a homogeneous, sensitive, and flexible HTS assay for protease activity.
• To demonstrate the assay's utility for clinically relevant proteases such as caspase 3 and beta-secretase (BACE).

Main Methods:

• Utilized a cyclic beta-galactosidase (beta-gal) enzyme donor peptide (ED) with protease-specific cleavage sequences.
• Linearization of the cyclic ED upon protease cleavage enables complementation with a beta-gal enzyme acceptor.
• Signal generation via fluorescent or chemiluminescent products catalyzed by active beta-gal.

Main Results:

• Developed an enzyme fragment complementation (EFC) assay for caspase 3 and BACE.
• The assay demonstrated linear signal response with enzyme concentration for both proteases.
• Achieved high sensitivity, detecting picogram levels of caspase 3 and nanogram levels of BACE.
• The BACE assay outperformed a commercial FRET-based assay in sensitivity.

Conclusions:

• The EFC protease assay is a simple, flexible, and highly sensitive technology.
• This assay is suitable for high-throughput screening of proteases and inhibitor discovery.
• The technology offers a robust platform for biochemical research and drug development.