Alanine. Molecular model of the amino acid alanine. Its chemical formula is C3.H7.N.O3. Atoms are represented as spheres and are colour-coded: carbon (blue), hydrogen (gold), oxygen (red) and nitrogen (dark blue). Amino acids are the building blocks of proteins. Alanine is a non-essential amino acid. It can be synthesised by the body and so does not need to come from the diet. Alanine plays an important role in the production of urea, the principal form in which mammals excrete nitrogenous compounds from the body.