A tetrapeptide has - COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with - NH 2 group attached to a chiral centre is

Question

A tetrapeptide has - COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with - NH 2 group attached to a chiral centre is (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

PLAN A peptide linkage is hydrolysed to two free amino acids.

C^{*}

is chiral carbon tetrapeptide has four amino acids joined by three peptide linkage.
-

COO H

group is on alanine part, thus it is at fixed

C

-terminal position in each combination.
Glycine is optically inactive thus it cannot be on the

N

- terminal side. Thus, possible combinations are
Phe-Gly-Val-Ala, Phe-Val-Gly-Ala,
Val-Gly-Phe-Ala, Val-Phe-Gly-Ala
Thus, in all four combinations are possible.

Q. A tetrapeptide has - COOH group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with −NH2​ group attached to a chiral centre is

Q. A tetrapeptide has - $COO H$ group on alanine. This produces glycine (Gly), valine (Val), phenyl alanine (Phe) and alanine (Ala), on complete hydrolysis. For this tetrapeptide, the number of possible sequences (primary structures) with $- N H_{2}$ group attached to a chiral centre is