A chromogenic substrate for solid-phase detection of phospholipase A₂

Area of Science:

• Biochemistry
• Enzymology
• Molecular Biology

Background:

• Phospholipase A₂ (PLA₂) enzymes play crucial roles in various biological processes.
• Sensitive and high-throughput detection methods for PLA₂ activity are essential for research and enzyme engineering.

Purpose of the Study:

• To develop a novel solid-phase detection method for quantifying phospholipase A₂ (PLA₂) activity.
• To establish a colorimetric assay for visualizing and screening PLA₂-producing microorganisms.

Main Methods:

• A new substrate, 1-octanoyloxynaphthalene-3-sulfonic acid, was synthesized and utilized for PLA₂ detection.
• The substrate is hydrolyzed by PLA₂ to release 1-naphthol-3-sulfonic acid, which then couples with a diazonium salt to form a detectable azo dye.
• The method was validated using purified Streptomyces and bovine pancreatic PLA₂, and applied to detect bacterial PLA₂ in recombinant Escherichia coli colonies.

Main Results:

• The developed method demonstrated considerable sensitivity in detecting purified PLA₂ on nitrocellulose membranes.
• A distinct colorimetric signal (red-purple azo dye) was observed upon PLA₂ activity.
• Recombinant Escherichia coli colonies producing active bacterial PLA₂ were successfully distinguished from those producing inactive mutants.

Conclusions:

• A sensitive and specific solid-phase detection method for phospholipase A₂ (PLA₂) has been established.
• This colorimetric assay facilitates high-throughput screening of PLA₂-producing microorganisms, supporting enzyme evolution studies.
• The method offers a valuable tool for biochemical research and biotechnological applications involving PLA₂.