Question

Which of the following statements are true for Edman degradation?
A. It is a method used for the determination of the primary structure of a protein
B. In this method only the amino-terminal amino acid of a peptide is labeled and removed
C. Ninhydrin is used to label the terminal amino acid
D. Phenyl isothiocyanate is used in the Edman reagent
Choose the correct answer from the options given below:

• A. A, B and D only
• B. A, B, and C only
• C. A, C and D only
• D. A, B, C and D

Hint:

Edman degradation:
Uses phenyl isothiocyanate (PITC).
Removes N-terminal amino acid sequentially.
Ninhydrin: used for amino acid detection, not Edman degradation.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Edman degradation is a method for protein sequencing.
It sequentially removes amino acids from the N-terminus.

Step 2: Key Formula or Approach:
No specific formula.
Need to understand the Edman degradation method.

Step 3: Detailed Explanation:
A. Edman degradation determines the primary structure (N-terminal sequencing) - correct.
B. Only the N-terminal amino acid is labeled and removed - correct.
C. Ninhydrin is not used in Edman degradation.
Ninhydrin is used for general amino acid detection - incorrect.
D. Phenyl isothiocyanate is the Edman reagent - correct.
Thus, A, B, and D are correct.

Step 4: Final Answer:
The correct statements are A, B, and D.
Hence, the correct option is (A).