(S-(Z))-2-Amino-4-(methylthio)-3-butenoic acid 143800-82-2 2-Amino-4-methylthio-3-butenoic acid 3-Butenoic acid, 2-amino-4-(methylthio)-, (S-(Z))- L-(cis)Amtb L-2-Amino-4-methylthio-cis-but-3-enoic acid