The molecule is a zwitterion obtained by transfer of a proton from the carboxy to the guanidino group of 5-guanidino-3-methyl-2-oxopentanoic acid; major species at pH 7.3. It is a tautomer of a 5-guanidino-3-methyl-2-oxopentanoic acid.
5-(diaminomethylideneazaniumyl)-3-methyl-2-oxopentanoate