valine

valine, an amino acid obtained by hydrolysis of proteins and first isolated by the German chemist Emil Fischer (1901) from casein. It is one of several so-called essential amino acids for fowl and mammals; i.e., they cannot synthesize it and require dietary sources. It is synthesized in plants and microorganisms from pyruvic acid (a product of the breakdown of carbohydrates). The chemical structure of valine is