Casein is the predominant protein in milk. Highlight the amino acids that would give the positive result for the following tests: biuret test, and xanthoproteic test? Will the oval... Casein is the predominant protein in milk. Highlight the amino acids that would give the positive result for the following tests: biuret test, and xanthoproteic test? Will the ovalbumin give a positive result also to the xanthoproteic test?
Understand the Problem
The question is asking for identification of specific amino acid sequences in casein that would yield a positive result for certain biochemical tests such as the biuret and xanthoproteic tests, along with highlighting the relevant amino acids.
Answer
Tyrosine (Y), Phenylalanine (F), and Tryptophan (W) will give positive results for the Xanthoproteic test. Yes, ovalbumin will give a positive result to the Xanthoproteic test.
The biuret test will give positive results for all proteins due to peptide bonds. The Xanthoproteic test will highlight these amino acids: Tyrosine (Y), Phenylalanine (F), and Tryptophan (W). Ovalbumin will also give a positive result for the Xanthoproteic test.
Answer for screen readers
The biuret test will give positive results for all proteins due to peptide bonds. The Xanthoproteic test will highlight these amino acids: Tyrosine (Y), Phenylalanine (F), and Tryptophan (W). Ovalbumin will also give a positive result for the Xanthoproteic test.
More Information
The Xanthoproteic test specifically detects aromatic amino acids due to their reactivity with nitric acid.
Tips
A common mistake is assuming all amino acids will show positive results for both tests, but only aromatic amino acids respond to the Xanthoproteic test.
Sources
- Experiment_729_Qualitative Testing of Amino Acids and Proteins - chem.libretexts.org
- Lab 10.pdf - EXPERIMENT 10 AMINO ACIDS AND PROTEINS - coursehero.com
- An Overview of Protein and Test for Protein - BYJU'S - byjus.com
