Theory of the Tests for Protein
Proteins are large biomolecules having long-chain polymers composed of amino acids. The main constituents of proteins are carbon, hydrogen, nitrogen, oxygen, and in some cases phosphorus and sulfur.
The following tests are conducted to detect the presence of proteins in a given sample.
- Biuret Test: In this test when a sample containing protein is treated with an alkaline solution and a drop of aqueous copper sulfate is added, a bluish-violet color appears. It is a qualitative test of protein.
- Xanthoproteic Test: If a sample containing proteins is treated with nitric acid, a yellow precipitate is formed. But when this solution is treated with alkali, it turns orange.
- Millon’s Test: The phenolic group present in proteins reacts with mercuric sulfate in the presence of sodium nitrite and sulfuric acid and turns the color of the solution red. Initially, when the sample containing protein is treated with Millon’s reagent, a white precipitate forms. Then after boiling, it turns into a brick-red colour.
- Ninhydrin Test: Proteins react with ninhydrin solution and turn it from a deep blue color to violet-pink or sometimes red color. Ninhydrin solution is prepared by dissolving 0.1gm of ninhydrin in about 100ml of distilled water.
Protein and Test for Protein
Test for Protein deals with the details of protein including its structure, properties, classification, and function as well as the details of different tests to detect proteins in a sample. The identification test for protein explains the principle and theory of each test, along with the materials and apparatus required, the procedures, observation, inferences, and discussion of the results of the tests.
Protein is an important biomolecule that is made up of one or more amino acid chains. Plants and animals synthesize these biomolecules and obtain them by consuming the plants. In this article, we will look into the meaning, theory, procedure, observation, results, and precautions of tests for proteins.
Table of Content
- What are Proteins?
- Test for Protein to Confirm its Presence
- Aim of the Protein Test
- Theory of the Tests for Protein
- Apparatus Set up and Chemicals Required for Protein Test
- Procedures of Test for Protein
- Observation and Inference
- Results and Discussion of Test for Protein
- Precautions
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