In this article we will discuss about the tests for estimation of polyphenol oxidase enzyme activity. Principle: The intensely yellow 2-nitro-5-thio-benzoic acid (TNB) with an absorption maximum at 412 nm reacts with quinones generated through enzymatic oxidation of 4-methyl-catechol (catechol oxidase) and 1, 4 di-hydroxy-benzene (laccase) to yield colourless adducts. The decrease in the absorbance of yellow- colour due to [...]
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: [...]
In this article we will discuss about the tests for estimation of lipase in plants. Principle: The quantity of fatty acid released in unit time is measured by the quantity of NAOH required to maintain pH constant. The milliequivalent of alkali consumed is taken as a measure of the activity of the enzyme. Materials: a. Substrate: Take 2 ml of [...]