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Visual detection of peptidase activity using fluorogenic substrates in a microtiter plate assay
G B Irvine1, M Ennis, C H Williams
1Division of Biochemistry, School of Biology and Biochemistry, Queen's University of Belfast, Northern Ireland, United Kingdom.
Analytical Biochemistry
|March 1, 1990
Summary
A new, cost-effective peptidase activity assay uses fluorogenic substrates for sensitive enzyme detection without a fluorometer. This method effectively locates enzyme activity during purification, as demonstrated with alpha-chymotrypsin and Helix aspersa aminopeptidases.
Area of Science:
- Biochemistry
- Enzymology
- Analytical Chemistry
Background:
- Peptidase activity assays are crucial for biochemical research and enzyme purification.
- Existing methods may require specialized equipment or lack sensitivity.
- A simple, accessible assay is needed for efficient enzyme characterization.
Purpose of the Study:
- To develop a simple, inexpensive, and sensitive assay for detecting peptidase activity.
- To enable enzyme activity localization during purification procedures.
- To validate the assay's utility with known enzymes and biological samples.
Main Methods:
- Utilized fluorogenic peptide substrates in a microtiter plate format.
- Detected liberated 7-amino-4-methyl coumarin fluorescence under UV light (356 nm).
- Employed alpha-chymotrypsin as a model enzyme and L-leucine 4-methyl-coumaryl-7-amide for aminopeptidase detection.
Main Results:
- The assay detected as little as 4 fmol of alpha-chymotrypsin.
- Successfully located enzyme activity in fractions after size-exclusion high-performance liquid chromatography.
- Identified two forms of aminopeptidase activity in Helix aspersa reproductive tissue extracts.
Conclusions:
- The developed assay is a sensitive, cost-effective tool for detecting peptidase activity.
- The method is particularly suitable for locating enzyme activity during purification processes.
- Demonstrated applicability in identifying specific enzyme activities in complex biological extracts.