| ChemSpiderID = 227 | PubChem = 6322 | SMILES = N[C@@H](CCCNC(N)=N)C(O)=O}} | Section2 = | Section3 = }} Arginine (abbreviated as Arg or R)'s an α-amino acid. The L-form's one of the 20 most common natural amino acids. Its codons are CGU, CGC, CGA, CGG, AGA, and AGG. In mammals, arginine's classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual. Infants are unable to meet their requirements and thus argi… (More on Arginine)