113857-87-7 Benzoic acid, 2-(((4-carboxy-4-((4-(((2-diamino-6-pteridinyl)methyl)amino)benzoyl)amino)butyl)amino)carbonyl)-, (S)- N(alpha)-(4-Amino-4-deoxypteroyl)-N(delta)-hemiphthaloyl-L-ornithine PT 523