Type of amino acids obtained by hydrolysis of proteins is :

We need to identify the type of amino acids obtained by hydrolysis of proteins.

Understand the structure of proteins.

Proteins are polymers of amino acids linked by peptide bonds ($$-CO-NH-$$). The peptide bond is formed between the $$\alpha$$-carboxyl group ($$-COOH$$) of one amino acid and the $$\alpha$$-amino group ($$-NH_2$$) of another.

Identify the type of amino acids.

In $$\alpha$$-amino acids, the amino group ($$-NH_2$$) is attached to the $$\alpha$$-carbon (the carbon atom directly adjacent to the carboxyl group). The general structure is:

$$H_2N - \underset{|}{C}H(R) - COOH$$

where $$R$$ is the side chain that varies between different amino acids.

Why $$\alpha$$-amino acids specifically?

All naturally occurring amino acids that make up proteins are $$\alpha$$-amino acids (with the exception of proline, which is technically an $$\alpha$$-imino acid). While $$\beta$$, $$\gamma$$, and $$\delta$$-amino acids exist (where the amino group is on the 2nd, 3rd, or 4th carbon from the carboxyl group respectively), they are not found in natural proteins.

The correct answer is Option (2): $$\alpha$$.