How are amino acids classified based on the relative position of the amino group with respect to the carboxyl group, and why are only α-amino acids obtained on hydrolysis of proteins?

Amino acids are classified based on the relative position of the amino group and carboxyl group on the alpha carbon atom. In α-amino acids, the amino and carboxyl groups are attached to the same carbon, forming the central alpha carbon. This class includes the building blocks of proteins. On hydrolysis of proteins, only α-amino acids are obtained because peptide bonds, linking amino acids in proteins, are specifically cleaved between the alpha carbon and nitrogen, releasing individual α-amino acids. Other amino acids, like β or γ, are not commonly found in proteins and do not result from typical protein hydrolysis.