#Threonine is an amino acid used in protein biosynthesis. It contains an amine group, a carboxyl group, and a side #chain containing a #hydroxyl group, making it an uncharged polar amino acid. It is essential for humans, which means the body cannot #synthesize it. It must be obtained from the diet. Threonine is synthesized from aspartate in bacteria. It is also worn for animal nutrition as nourish additives.