Plants are to face different untoward conditions like draught, salinity of water, different infections from pathogens etc. In those processes ,there is overproduction of ROS including superoxide. SOD is an enzyme which is upregulated in all those stress conditions in plants. The overexpressed SOD now dismutes superoxide to form less harmful hydrogen peroxide and oxygen. So, SOD is often upregulated in plants.
For sample:
Test-tube extract at varying concentrations (20, 40, 60, 80, 100, etc.)
Add 3.4ml phosphate buffer
Also add 0.6ml (600µl) H2O2 solution
After that, incubate for ten minutes in the dark.
Measure the OD at 230 nm.
The assay of SOD employs xanthine and xanthine oxidase to generate superoxide radicals which on reaction with 2-(4-iodophenyl) -5-phenyltetrazolium chloride (INT) forms a red formazan dye. The absorbance is measured at 505nm by a spectrophotometer. SOD is measured from the degree of inhibition of this reaction and expressed as units/ml. One unit is equal to the amount of sod to cause 50 percent inhibition of reduction rate. For details, my paper on serum SOD as tuberculosis diagnostics may be gone through.
Rashmi Tripathi You don't use the SOD assay. You look at the consumption of H2O2. Almost everything in bio-sample absorbs at 260 nm.
There are some rationale behind that;
i. stress response by the plant through upregulation of antioxidant enzymes like SOD to counteract oxidative damage.
ii. Reactive oxygen species scavenging
iii. Adaptive mechanism to protect plants from oxidative damage caused by environmental stresses like salinity, drought etc
Kabiru Ayantayo Amusan Your post has nothing to do with the question.
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