In this article we will discuss about the tests for estimation of peroxidase in plants.

Principle:

The enzyme peroxidase catalyses the oxidation of substrate by oxygen generated from the decom­position of hydrogen peroxide:

2H2O2 → 2H2O + O2

Substrate + O2 → Oxidized substrate.

Requirements:

(a) Reagents:

1. Hydrogen peroxide (H2O2) — 0.2%

2. Catechol soln. — 0.5%

(b) Glass-wares:

1. Test tubes, Pipette, Mortar and Pestle, Measuring Cylinder, Linen cloth, Balance with weight box etc.

(c) Preparation of enzyme extract:

Fresh seedlings of rice are taken and the endosperms are removed from the seedlings. Then 5 gm. of plant material is weighed and crushed in a mortar with the help of a pestle. Then an extract of about 50 ml is prepared and strained through a linen cloth and final volume is made up to 50 ml my addition of dist. water.

Test Procedure:

1. The reaction mixture is made in the following manner. In each tube 1 ml of catechol and 1 ml of H2O2 soln. are taken. Then 1 ml of enzyme extract is added to it.

2. Finally, the mixture is shaken gently and allowed to stand for 1-5 minutes to develop colour.

3. The intensity of colour formed in each reaction mixture at varied duration is recorded opti­cally by denoting ‘+’ sign.

4. Each set is replicated at least thrice for getting better results.

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