The molecule is a dipeptide zwitterion obtained by transfer of two protons from the carboxy to the amino and guanidino groups of beta-Asp-Arg; major species at pH 7.3. It is a tautomer of a beta-Asp-Arg.
(2S)-2-[[(3S)-3-azaniumyl-3-carboxylatopropanoyl]amino]-5-(diaminomethylideneazaniumyl)pentanoate