Question

Match List-I with List-II


List-I (Method) & List-II (Use in Protein Chemistry)
(A). Hydrazinolysis & (I). Site-specific cleavage of a polypeptide or protein
(B). Acid/Alkaline Hydrolysis & (II). Amino acid composition analysis of a polypeptide
& or protein
(C). Tryptic Digestion & (III). N-terminal determination of a polypeptide or protein
(D). Sanger Degradation & (IV). C-terminal determination of a polypeptide or protein


Choose the correct answer from the options given below:

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
• (A) - (IV), (B) - (II), (C) - (I), (D) - (III)
• (A) - (IV), (B) - (III), (C) - (I), (D) - (II)

Hint:

Sanger's reagent (FDNB) is the classic chemical used to label the amino-terminus (N-terminal) amino acid of a polypeptide.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Determining protein structures and amino acid sequences requires specific chemical and enzymatic cleavage methods.

Step 2: Detailed Explanation:
Let us match each analytical method to its function in protein chemistry:
- (A) Hydrazinolysis: A chemical method where a polypeptide is treated with hydrazine at high temperatures. It cleaves all peptide bonds, converting all amino acid residues into amino acid hydrazides except for the C-terminal amino acid, which remains free. This is used for C-terminal determination (IV).
- (B) Acid/Alkaline Hydrolysis: Complete chemical hydrolysis of peptide bonds into individual free amino acids, allowing for downstream quantitative amino acid composition analysis (II).
- (C) Tryptic Digestion: The enzyme trypsin cleavage is highly selective, hydrolyzing peptide bonds on the carboxyl side of lysine and arginine residues. This is used for site-specific cleavage (I).
- (D) Sanger Degradation: Utilizes 1-fluoro-2,4-dinitrobenzene (Sanger's reagent) to bind to and identify the free \(\alpha\)-amino group at the N-terminus (III).
This gives the sequence: (A)-(IV), (B)-(II), (C)-(I), (D)-(III).

Step 3: Final Answer:
Hence, the correct option is (C).