The provided text discusses three biochemical tests for proteins. Here is a concise summary of each test:
1. **Biorate Test:** This test involves the formation of a chelate complex when a peptide bond reacts with a solution containing CuSO4 (copper sulfate) and a chelating salt. The resulting chelate complex produces a violet coloration, indicating the presence of a peptide bond.
2. **Ninhydrin Test:** In this test, an amino acid undergoes nitration when treated with concentrated HNO3 (nitric acid) and ninhydrin. This reaction leads to the formation of a four-ringed heterocyclic compound, resulting in a purple coloration. It detects the presence of certain aromatic amino acids.
3. **Xanthoprotic Test:** The xanthoprotic test starts with the nitration of an aromatic amino acid with concentrated HNO3. This nitration reaction initially yields a yellow coloration. However, when an alkali like NaOH is added, it further reacts to form an alkoxide ion, resulting in an orange coloration. This test identifies amino acids with aromatic groups.
These tests are used in laboratories to detect the presence of specific chemical groups or bonds in protein samples.
Sure, here are the key facts extracted from the text:
1. Biochemical tests for protein include the biorate test, ninhydrin test, and xanthoprotic test.
2. The biorate test involves the use of reagents like CuSO4 and a chelating salt to detect peptide bonds, resulting in a violet coloration.
3. The ninhydrin test uses ninhydrin solution to nitrate amino acids, leading to a purple coloration.
4. The xanthoprotic test uses concentrated HNO3 and an alkali like NH4OH to detect aromatic amino acids, changing color from yellow to orange.
5. Each test has a specific chemical reaction principle that helps in identifying the presence of amino acids or peptide bonds in a given sample.
These facts summarize the key information from the text without including opinions or explanations.