Which biochemical test is used to detect the presence of peptide bonds in proteins, giving a violet-purple coloration with alkaline copper sulfate?
Answer and explanation
Correct answer: B. Biuret test
- Step 1: Compounds containing two or more peptide bonds react with Cu2+ ions in alkaline solution. Step 2. Cu2+ coordinates with peptide nitrogen atoms to form a violet-purple coordination complex (Biuret test). Answer: Biuret test. Why not the others: Ninhydrin tests free amino acids giving Ruhemann's purple; Molisch test detects carbohydrates; Barfoed's distinguishes monosaccharides from disaccharides.
Practise more Organic Reactions, Biomolecules and Pharmaceutical Principles.
Free questions with an explanation for every one, and full timed Medical College Admission Test (Bangladesh) mock tests.
More Organic Reactions, Biomolecules and Pharmaceutical Principles questions
- Why is Phenol significantly more acidic than aliphatic alcohols like Ethanol? (Hard)
- What observation confirms the presence of Phenol when treated with neutral Ferric chloride (FeCl3) solution?
- What product is formed when Phenol is treated with excess Bromine water at room temperature?
- What is the active pharmaceutical chemical name of Aspirin, synthesized by acetylating salicylic acid?
- What is the major chemical constituent of 'Oil of Wintergreen', used as a topical analgesic ointment?
- Why is Sucrose (cane sugar) classified as a non-reducing disaccharide? (Hard)