Superoxide Dismutases (SODs) are metalloenzymes crucial for cellular antioxidant defense, catalyzing the dismutation of the superoxide anion to molecular oxygen and hydrogen peroxide. Three characterized types include copper/zinc (Cu/Zn), manganese (Mn), and iron (Fe) SODs, with widespread distribution in plants and animals, particularly in organs such as the brain, liver, heart, erythrocytes, and kidney. Maintaining appropriate SOD levels in cellular and extracellular environments is crucial for the prevention of diseases associated with oxidative stress, including neurodegenerative disorders like Alzheimer’s, Parkinson’s, and Huntington’s diseases.

RayBio® Superoxide Dismutase (SOD) Activity Assay Kit provides a simple, reproducible, and sensitive tool for measuring SOD activity in plasma, serum, cell lysates and other biological samples. In this assay, superoxide anions, generated through xanthine conversion to uric acid and hydrogen peroxide by xanthine oxidase (XO), reduce WST-1 to water-soluble formazans. The absorbance at 450nm measures the formazans, and SODs modulate the reduction reaction rate by diminishing superoxide anion concentrations. Consequently, the percentage of inhibition in the reduction reaction serves as a quantifiable indicator of SOD activity.

• Microplate reader capable of measuring absorbance at 450 nm
• Precision pipettes to deliver 2 µL to 1 mL volumes
• Multi-channel pipettes to deliver 20 μL to 200 μL volumes
• Tubes to prepare sample dilutions
• Distilled or deionized water
• 50 ml conical tubes

Each Superoxide Dismutase standard and samples should be assayed in duplicate or triplicate. A freshly prepared standard curve should be used each time the assay is performed.

1. Add 20 μL of the diluted SOD standards or unknown samples to the 96-well Microplate.
2. Add 200 μL Substrate Working Solution to each well. Mix thoroughly. Read and record absorbance at 450nm (A1 Reading).
3. Initiate the reaction by adding 30 μL XO Working Solution into each well and mix thoroughly.
4. Incubate for 30 minutes at room temperature.
5. Read and record absorbance at 450nm (A2 Reading).