Purity ≥98%. Arginine (abbreviated as Arg or R) encoded by the codons CGU, CGC, CGA, CGG, AGA, and AGG is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated -+NH3 form under biological conditions), an α-carboxylic acid group (which is in the deprotonated -COO- form under biological conditions), and a side chain of a 3-carbon aliphatic straight chain capped by a complex guanidinium, classifying it as a charged (at physiological pH), aliphatic amino acid. Arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual. Synonyms: 2-Amino-5-guanidinopentanoic acid; L-(+)-Arginine; L-Arg CAS No: 74-79-3