Amino acids are compounds in which the hydrogen atoms of a carboxylic acid carbon are replaced by the amino group. The amino acid molecule contains two functional groups, an amino group and a carboxyl group which is similar to hydroxy acids. Amino acids can be divided into α-, β-, γ-...w-amino acids according to different positions of the amino group attached to the carbon chain. However, the amino acids obtained after proteolysis are all α-amino acids, and there are twenty kinds, which are the basic unit of protein.
Amino acids are the basic substances that make up the protein needed for animal nutrition. It is an organic compound containing a basic amino group and an acidic carboxyl group.The amino group attached to the α-carbon is an α-amino acid. The amino acids constituting the protein are mostly α-amino acids.