A chemiluminescence-based catalase assay using H₂O₂-sensitive CdTe quantum dots.

Area of Science:

• Analytical Chemistry
• Biochemistry
• Materials Science

Background:

• Catalase (CAT) is a crucial enzyme involved in cellular defense against oxidative stress.
• Accurate and rapid determination of CAT activity is essential for various biological and medical applications.
• Existing methods for CAT activity assay can be time-consuming or require complex sample preparation.

Purpose of the Study:

• To develop a novel, sensitive, and rapid chemiluminescence-based method for determining catalase activity.
• To utilize hydrogen peroxide-sensitive Cadmium Telluride (CdTe) quantum dots (QDs) for CAT detection.
• To establish a convenient assay suitable for real-world sample analysis.

Main Methods:

• A chemiluminescence system employing CdTe quantum dots and hydrogen peroxide (H₂O₂) was established.
• The catalytic activity of catalase was assessed by monitoring the reduction in chemiluminescence intensity due to H₂O₂ consumption.
• The Michaelis constant (K_m) was determined, and limit of detection (LOD) and linear range were calculated.

Main Results:

• The chemiluminescence intensity of the CdTe/H₂O₂ system decreased proportionally to CAT activity.
• The calculated Michaelis constant (K_m) was 519 ± 27 mM, demonstrating accurate K_m measurement potential.
• The assay exhibited a low LOD of 4.5 unit/mL within a 2s incubation time and a linear range of 6-400 unit/mL.

Conclusions:

• The developed quantum dot-based chemiluminescence assay provides a sensitive, simple, and rapid method for catalase activity determination.
• The assay's convenience, not requiring QD conjugation to biomolecules, makes it suitable for practical applications.
• This method offers a valuable tool for assessing catalase levels in various samples.