Dual-substrate plate diffusion assay for proteases

Area of Science:

• Biochemistry
• Enzymology
• Analytical Chemistry

Background:

• Endopeptidases are crucial enzymes involved in various biological processes.
• Accurate quantification of endopeptidase activity is essential for research and diagnostics.
• Existing methods for protease activity assay may have limitations in simplicity or sensitivity.

Purpose of the Study:

• To develop a novel and straightforward plate diffusion assay for quantifying endopeptidase activity.
• To validate the assay's reliability and sensitivity for enzyme activity measurement.

Main Methods:

• A plate diffusion assay was designed utilizing 1% casein and 1% gelatin as substrates within a 1.5% agar medium.
• Endopeptidases (proteases) were applied to the prepared agar plates.
• Distinct zones of hydrolysis were observed and measured around the enzyme application points.

Main Results:

• The assay produced clear zones of hydrolysis, visually similar to immunoprecipitation bands.
• A linear relationship was established between the logarithm of enzyme activity and the diameter of the hydrolysis zones.
• The assay demonstrated sensitivity across a wide range of enzyme activity, from 0.01 to over 100 International Units (IU)/ml.

Conclusions:

• The developed plate diffusion assay is a simple, effective, and sensitive method for quantifying endopeptidase activity.
• This assay provides a reliable alternative for enzyme activity determination in various scientific applications.
• The distinct zones and linear proportionality offer a robust visual and quantitative measure of protease function.