What is the reaction involved in Xanthoproteic test?

What is the reaction involved in Xanthoproteic test?

The Xanthoproteic test uses a nitration reaction to determine the presence of proteins in a solution. When the sample is treated with a hot, concentrated nitric acid it reacts with aromatic amino acids such as phenylalanine, tyrosine and tryptophan and forms a yellow colored product known as Xantho protein.

What do you mean by Xanthoproteic reaction?

Definition of xanthoproteic reaction : the reaction of warm concentrated nitric acid with tyrosine or tyrosine-containing proteins (as in human skin) to form a yellow color that is intensified to orange-yellow by the addition of alkali.

Why phenylalanine does not respond to Xanthoproteic?

Principle of Xanthoproteic Test Benzene ring-containing amino acids like phenylalanine don’t give a positive test to this test because the phenyl group in phenylalanine is very stable, which doesn’t react with nitric acid in the conditions of this test.

What is the product of a positive Xanthoproteic test?

The positive result of xanthoproteic reaction gives: tyrosine, tryptophan and phenylalanine (only after extended heating time).

What is Xanthoproteic test for?

Xanthoproteic test is used to detect amino acids containing an aromatic nucleus (tyrosine, tryptophan and phenylalanine) in a protein solution which gives yellow color nitro derivatives on heating with conc. HNO3. The aromatic benzene ring undergoes nitration to give yellow colored product.

How do you make Xanthoproteic reagent?

Procedures

1. Take 1ml test solution in dry test tube.
2. Similarly, take 1ml distilled water in another test tube as control.
3. Add 1ml of conc. HNO3 in all test tubes and mix well.
4. Cool the solution under tap water.
5. Now add 2ml of 40 % NaOH to all test tubes.
6. Look for the color development.

What is xanthoproteic test for?

Does phenylalanine give xanthoproteic test?

The xanthoproteic test is specific for aromatic compounds such as tyrosine, tryptophan and phenylalanine.

Is phenylalanine positive for Xanthoproteic test?

HNO3. The aromatic benzene ring undergoes nitration to give yellow colored product. Phenylalanine gives negative or weakly positive reaction though this amino acid contains aromatic nucleus because it is difficult to nitrate under normal condition.

What is Millon test?

Millon’s test is an analytical test used for the detection of the amino acid tyrosine, which is the only amino acid containing the phenol group. Millon’s test is a specific test for tyrosine, but it is not a specific test for protein as it also detects the phenolic group present in other compounds as well.

What is Xanthoproteic acid test?

Why is Xanthoproteic important?

The xanthoproteic reaction is a method that can be used to detect a presence of protein soluble in a solution, using concentrated nitric acid. The test gives a positive result in amino acids carrying aromatic groups, especially in the presence of tyrosine.

What is the purpose of The xanthoproteic reaction?

The xanthoproteic reaction is a method that can be used to determine the amount of protein soluble in a solution, using concentrated nitric acid. The test gives a positive result in amino acids carrying aromatic groups, especially in the presence of tyrosine.

What are the signs of the xantoprotein protein recognition reaction?

The main sign of the xantoprotein protein recognition reaction is the presence of a benzene ring or heterocycle in the amino acid molecule. Of the protein amino carboxylic acids, two aromatic acids are distinguished, in which there is a phenyl group (in phenylalanine) and a hydroxyphenyl radical (in tyrosine).

How is The xanthoproteic test used to detect amino acids?

Xanthoproteic test is used to detect amino acids containing an aromatic nucleus ( tyrosine, tryptophan and phenylalanine) in a protein solution which gives yellow color nitro derivatives on heating with conc. HNO3. The aromatic benzene ring undergoes nitration to give yellow colored product.

Why does a positive xanthoproteic test turn yellow?

If the test is positive the proof is neutralized with an alkali, turning dark yellow. The yellow colour is due to xanthoproteic acid which is formed due to nitration of certain amino acids, most common examples being tyrosine and tryptophan.