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The presence of protein is tested by the Biuret test for proteins.

The presence of protein is tested by the Biuret test for proteins. The Biurette reagent made of sodium hydroxide and copper (II) sulphate helps in determining the presence of protein in a sample.

It is important to identify the proteins to understand their functions. It helps in characterizing the binding of proteins to other proteins, nucleic acids, or too small molecules. It also plays a major role in drug discovery.

Gel electrophoresis is used to separate proteins according to their size.

Proteins consist of hundreds or thousands of smaller units called amino acids that are attached in long chains to each other. It is possible to combine 20 different types of amino acids to make a protein.

The two types of proteins are globular proteins and fibrous proteins.

Proteins undergo hydrolysis resulting in the formation of α-amino acids.

Two amino acids are linked together with the loss of a water molecule. A number of amino acids joined by peptide bonds form a chain of polypeptides, and each unit of amino acids in a polypeptide is called a residue.

A monomer is a molecule that forms larger polymer molecules and is a building block of protein. For instance, an amino acid acts as the protein building blocks. The polymer of protein is a monomer series.

Proteins are the essential biomolecules, consisting of one or more long chains of amino acid residues. They are large macromolecules, which play a vital role in growth and development, therefore it is called as the building blocks of the body. They are the class of biologically important compounds with high molecular weight.

Proteins are perhaps the most complex organic materials produced in nature. Plants build up their proteins from carbon dioxide, water, and minerals in the presence of sunlight, whereas animals derive it from eating plants.

Among various types of proteins, Albumin and globulin are the two different types of protein present in our blood cells, and they play an important role in :

Maintaining the oncotic pressure of the blood plasma.

Prevents the fluid from leaking out of the blood vessels.

It helps in the transportation of ions, lipids, and other hormones.

Proteins are the main constituents of all living cells and are the building blocks of life. They play an essential role in the  growth and development  of cells and tissues. Proteins have a high molecular mass, long chain polymer, composed of α-amino acids and contain carbon, hydrogen, nitrogen, oxygen and sometimes phosphorus and sulfur.

The following are the simple tests carried to find the presence of proteins in the given food samples.

The compounds with peptide linkage undergo this test. Proteins are polypeptides of amino acids linked together by peptide bonds. An alkaline solution of protein is treated with a drop of aqueous copper sulfate and a bluish violet color is obtained. Note:  Formation of violet coloration confirms the presence of Proteins.

Proteins on treatment with nitric acid give a yellow or orange color. Concentrated nitric acid is used for nitration. On the treatment of nitric acid, proteins give yellow precipitate which turns to orange color on treatment with alkali. Note:  The appearance of a yellow color solution confirms the presence of proteins.

Phenolic group of tyrosine of proteins reacts with mercuric sulfate in the presence of sodium nitrite and sulfuric acid to give red color. Millon’s test is given by proteins containing phenolic amino acids. Gelatin does not give this test. First, a white precipitate is formed when proteins are treated with millions reagent and then turns to brick-red color on boiling, this confirms the presence of proteins. Note:  The appearance of brick red color solution confirms the presence of proteins.

Proteins react with pyridine solution of ninhydrin and change to a colored solution from a deep blue to violet-pink or sometimes even to a red color. Ninhydrin solution is prepared by dissolving 0.1gm of ninhydrin in about 100ml of distilled water. But this solution of ninhydrin is unstable and can be kept for two days. Note:  The appearance of violet color solution confirms the presence of proteins.

Aim To perform a simple test to identify the presence of proteins in the given plant and animals food sample. Materials Required

If you are using a solid sample like paneer, or apple, first crush or grind into a smooth paste using mortar and pestle. Chemical required

The given food sample – Milk, Apple, Paneer, Butter, Cheese, etc contains proteins in it.

The protein test is used to measure the total amount of protein present in the given blood samples. Usually, Doctors prescribe this test if a patient is suffering from any of the  food deficiency  diseases or other disorders like fatigue, weight loss, kidney or liver disease, etc.

This was a simple experiment which is used to check for the presence of protein and peptide bonds in a protein.

For more additional information about protein, its structure, functions, visit  StudySolver Biology

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 The appearance of bluish- violet color confirms the presence of Proteins.

 The appearance of yellow color confirms the presence of proteins.

 The appearance of brick red color confirms the presence of proteins.

 The appearance of deep blue or purple color confirms the presence of proteins.