LIFE SCIENCE

Detailed explanation-1: -A peptide has two ends: the end with a free amino group is called the N-terminal amino acid residue. The end with a free carboxyl group is called the C-terminal amino acid residue. Peptides are named from the N-terminal acid residue to the C-terminal amino acid.

Detailed explanation-2: -The normal pattern shows the following N-terminal amino acids in order of diminishing quantities: aspartic acid, glutamic acid, valine, alanine, tyrosine, leucines, and glycine.

Detailed explanation-3: -Sanger’s reagent reacts with amino groups in amino acids to produce dinitrophenyl amino acids. These dinitrophenyl amino acids are stable under acid hydrolysis conditions that break peptide bonds. Thus, Sanger’s reagent is used for the identification of N-terminal of peptide chain.

Detailed explanation-4: -2, 4-dinitrofluorobenzene is called Sanger’s reagent. When this reagent reacts with amino group of peptide chain, it form 2, 4-dinitrophenyl derivatives which on hydrolysis form DNP derivatives of amino acids.