3-(Amidinothio)propionic acid 3-(Aminoiminomethyl)thiopropanoic acid 5398-29-8 AI3-18125 EINECS 226-430-0 NSC 4453 Propanoic acid, 3-((aminoiminomethyl)thio)- Propionic acid, 3-(amidinothio)- (8CI) beta-Isothiureidopropionic acid