- Sep 15, 2018 -
Amino acids are compounds substituted by amino groups for hydrogen atoms of carboxylic acids. Amino acids contain amino and carboxyl groups. Similar to hydroxyl acids, amino acids can be divided into alpha-, beta-, gamma-... w-amino acids according to the position of amino groups attached to the carbon chain. However, the amino acids obtained from protein hydrolysis are all alpha-amino acids, and only twenty or so are the basic units of protein.
Amino acids are the basic substances that constitute the protein needed for animal nutrition. It is an organic compound containing basic amino acids and acidic carboxyl groups. Amino groups are alpha amino acids on the alpha carbon. Most of the amino acids that make up proteins are alpha amino acids. 
Amino acids can play the following roles in human body through metabolism: 1) synthesis of tissue proteins; 2) conversion to ammonia-containing substances such as acids, hormones, antibodies, creatine; 3) conversion to carbohydrates and fats; 4) oxidation to carbon dioxide and water and urea to produce energy.