JEE Chemistry 2023 Question with Solution

Given: On complete hydrolysis, the peptide produces $3$ glycine, $2$ leucine and $2$ valine residues per mole of peptide.

Find: The number of peptide linkages.

A peptide containing total amino acid residues:

$$3 + 2 + 2 = 7$$

For a peptide chain, number of peptide linkages = number of amino acids $- 1$.

$$7 - 1 = 6$$

Therefore, the number of peptide linkages is $6$.

Given: The short peptide gives $3$ moles of glycine, $2$ moles of leucine and $2$ moles of valine on hydrolysis.

Find: Total peptide bonds present.

First count the total number of amino acid units in the peptide:

$$\begin{aligned} \text{Total residues} &= 3 + 2 + 2 \\ &= 7 \end{aligned}$$

In a linear peptide, if there are $n$ amino acids, then the number of peptide linkages is:

$$n - 1$$

Substituting $n = 7$:

$$7 - 1 = 6$$

Therefore, the peptide contains $6$ peptide linkages.