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Flow-injection assay of catalase activity
Hiroyuki Ukeda1, Yukiko Adachi, Masayoshi Sawamura
1Department of Bioresources Science, Faculty of Agriculture, Kochi University, Monobe B-200, Nankoku 783-8502, Japan. hukeda@cc.kochi-u.ac.jp
Summary
A new flow-injection assay (FIA) system enables precise measurement of catalase activity. This method uses immobilized uricase to generate hydrogen peroxide, which is then decomposed by catalase, allowing for accurate and rapid enzyme activity monitoring.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Enzyme Assays
Background:
- Catalase is a crucial enzyme for cellular protection against oxidative stress.
- Accurate and efficient methods for measuring catalase activity are essential for research and diagnostics.
- Existing methods may lack the speed, sensitivity, or automation required for high-throughput analysis.
Purpose of the Study:
- To develop and validate a novel flow-injection assay (FIA) system for the rapid and sensitive determination of catalase activity.
- To optimize the FIA system using immobilized uricase for hydrogen peroxide generation.
- To assess the applicability of the FIA system for monitoring enzyme inactivation, such as by glycation.
Main Methods:
- Construction of a dual-line flow-injection assay (FIA) system.
- Immobilization of an oxidase (uricase) for continuous hydrogen peroxide generation.
- Amperometric detection of dissolved oxygen changes using a Clark-type oxygen electrode.
- Optimization of reaction conditions and system parameters.
Main Results:
- Uricase was identified as the most suitable oxidase for hydrogen peroxide generation due to stability and efficiency.
- The FIA system achieved a linear calibration curve for catalase activity from 21 to 210 units/mg.
- High reproducibility (CV < 2%) was demonstrated over 35 successive determinations.
- A sampling frequency of approximately 15 samples per hour was achieved.
Conclusions:
- The developed FIA system provides a robust and efficient platform for quantifying catalase activity.
- The system is capable of monitoring catalase inactivation, demonstrated by its application to glycation studies.
- This novel assay offers advantages in speed, reproducibility, and automation for catalase activity measurements.