The molecule is a zwitterionic form of L-lombricine where the carboxy and phosphate groups are anionic and the amino and guanidino groups are cationic; major species at pH 7.3. It is a tautomer of a L-lombricine.
(2S)-2-azaniumyl-3-[2-(diaminomethylideneazaniumyl)ethoxy-oxidophosphoryl]oxypropanoate