Molecular model of Alanine (C3. H7. N. O2), a small non-essential, genetically coded, amino acid in humans used for protein construction and involved in the metabolism of tryptophan and vitamin pyridoxine. Alanine is synthesised by the body and constitutes a source of energy for muscles and central nervous system, but also helps in the metabolism of sugars and organic acids. Atoms are represented as spheres and are colour-coded: carbon (black), hydrogen (white), Nitrogen (blue), and Oxygen (red). Illustration.