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Cat. No.: TSDDAK-100 (for 100T)

Cat. No.: TSDDAK-250 (for 250T)

Description

Total Superoxide Dismutase Assay Kit is a kit based on the WST-8 colorimetric reaction, used to detect the activity of superoxide dismutase (SOD) in cells, tissues, or other samples through colorimetry.

Superoxide dismutase (SOD) catalyzes the dismutation of superoxide anions to produce hydrogen peroxide (H₂O₂) and oxygen (O₂), making it an important antioxidant enzyme in organisms.

Currently, there are various methods for measuring SOD activity. The NBT (Nitro Blue Tetrazolium) method is widely used due to its convenience. However, the formazan dye produced by the NBT method has poor water solubility and can interact with reduced xanthine oxidase, leading to less than 100% inhibition, which affects the sensitivity and accuracy of detection. The cytochrome C method is another common method for detecting SOD activity, but cytochrome C has high oxidative activity and is easily interfered with by reducing agents in the sample. Additionally, this method requires continuous measurement of absorbance values, making it less sensitive for SOD detection and not very suitable for large-scale sample testing.

The more advanced methods for measuring SOD include the WST-1 method and the WST-8 method, with the WST-8 method being more stable and sensitive than the WST-1 method. This kit uses the WST-8 method, which is more stable and sensitive among the current SOD measurement methods, capable of detecting superoxide dismutase as low as 0.5 U/ml.

The reaction product of WST-8 is a stable, water-soluble product that allows for the measurement of SOD activity through absorbance detection at a single time point, making it suitable for high-throughput screening studies. When measuring SOD enzymatic activity using the WST-8 method, the maximum inhibition percentage can approach 100%, and it is not affected by some common interfering factors, significantly improving detection results compared to other common methods.

This kit outperforms similar products for total SOD activity detection kits (NBT method). The purpose of this product is the same as that of similar products for total SOD activity detection kits (NBT method), but the absorbance change value caused by the same amount of SOD is significantly greater than that of the NBT method, and it has a wider linear range. The SOD sample preparation solution provided by this kit can directly lyse cells without homogenization, making the operation more convenient.

The detection of this kit is not affected by hydrogen peroxide in the sample. Many cell and tissue samples contain endogenous hydrogen peroxide, which can interfere with SOD detection. This kit effectively removes the interference of hydrogen peroxide in conventional samples by adding an appropriate amount of catalase and other special methods. For example, when detecting SOD standards, adding up to 0.1 mM hydrogen peroxide to the standard does not significantly affect the detection results.

This kit can detect SOD activity in biological samples such as cell or tissue homogenate supernatants, whole blood, red blood cell extracts, and serum.

Components

• SOD Sample Preparation Solution
• SOD Detection Buffer
• WST-8
• Enzyme Solution
• Reaction Initiator (40X)

Principle

WST-8 can react with superoxide anions (O₂⁻·) produced by the catalysis of xanthine oxidase (XO) to generate a water-soluble formazan dye. Since SOD can catalyze the dismutation of superoxide anions, this reaction step can be inhibited by SOD. Therefore, the activity of SOD is inversely related to the amount of formazan dye produced. By performing colorimetric analysis of the WST-8 product, the enzymatic activity of SOD can be calculated.

Storage

Store at -20°C, valid for six months. WST-8 should be stored protected from light.

Precautions

• Test samples can be stored at -70°C for one month. Note that repeated freeze-thaw cycles can lead to partial inactivation of SOD.
• If a kit cannot be used up within three times, the WST-8 should be aliquoted appropriately during the first use to avoid decreased detection performance due to repeated freeze-thaw cycles.
• The diluent used for standard dilution should be as consistent with the sample as possible. When samples are prepared using the SOD sample preparation solution provided by the kit, the standards should also be diluted using the SOD sample preparation solution. When the sample is blood or other untreated samples, the SOD detection buffer provided by the kit should be used to dilute the standards.
• Antioxidants can interfere with the detection of this kit. For example, 0.1 mM ascorbic acid and 5 mM GSH can significantly increase the measured absorbance. Although the sample may not have color, setting blank control 3 as described in the instructions can eliminate the interference of antioxidants in the sample.
• This product is for scientific research use by professionals only and is not intended for clinical diagnosis or treatment, food, or drugs, and should not be stored in ordinary residences.
• For your safety and health, please wear a lab coat and disposable gloves during operation.