Related Experiment Video
Updated: Jul 19, 2026
08:08
An Assay for Measuring the Activity of Escherichia coli Inducible Lysine Decarboxyase
Published on: December 20, 2010
A general coupled spectrophotometric assay for decarboxylases.
1Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.
Analytical Biochemistry
|June 1, 1988
Summary
A new spectrophotometric method accurately measures decarboxylase activity by tracking CO2 production. This sensitive assay is useful for various decarboxylase enzymes in biochemical research.
Area of Science:
- Biochemistry
- Enzymology
- Spectrophotometry
Background:
- Decarboxylases are crucial enzymes involved in various metabolic pathways.
- Accurate and sensitive assays are needed to study decarboxylase activity.
- Existing methods may lack speed, continuous monitoring, or sensitivity.
Purpose of the Study:
- To develop a rapid, continuous spectrophotometric method for assaying decarboxylase activity.
- To establish a sensitive detection limit for carbon dioxide (CO2) liberation.
- To validate the method using known decarboxylase enzymes.
Main Methods:
- A coupled enzyme system was employed for CO2 detection.
- Carbon dioxide (CO2) reacted with phosphoenolpyruvate and phosphoenolpyruvate carboxylase.
- Malate dehydrogenase coupled the reaction to NADH oxidation, monitored spectrophotometrically at 340 nm.
Main Results:
- The method provides a continuous and accurate measurement of decarboxylase activity.
- A decrease in absorbance at 340 nm directly correlates with enzyme activity.
- The assay can detect as little as 1 nmol of CO2/min.
- Successfully applied to lysine decarboxylase, orotidine-5'-phosphate decarboxylase, and 4'-phosphopantothenoyl-L-cysteine decarboxylase.
Conclusions:
- A novel, rapid, and continuous spectrophotometric assay for decarboxylases has been successfully developed.
- The method offers high sensitivity for CO2 detection, suitable for various decarboxylase studies.
- This assay provides a valuable tool for biochemical and enzymatic research involving decarboxylases.
Related Concept Videos
01:16Spectrophotometry: Introduction
Spectrophotometry is the quantitative measurement of the absorption, reflection, diffraction, or transmission of electromagnetic radiation through a material as a function of the intensity and wavelength of the radiation. A spectrophotometer is a device used to measure the change in the radiation intensity caused by its interaction with the material.
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
The essential components of a spectrophotometer include a source of electromagnetic radiation, a slot for placing a material to be analyzed, and a...
01:28IR and UV–Vis Spectroscopy of Carboxylic Acids
In IR spectroscopy of carboxylic acids, the C=O bond shows a characteristic band between 1710 and 1760 cm⁻¹, and the O–H bond exhibits a broad band between 2500 and 3300 cm⁻¹.
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...
However, the stretching absorptions for the C=O bond vary depending on the structure of carboxylic acids. The C=O bond of the free carboxylic acids shows a higher stretching frequency, 1760 cm−1, while H-bonded carboxylic acids (dimers) exhibit stretching absorptions at a lower frequency, 1710 cm−1. The C=O bond of the...