Hydrolyzes ureidoacrylate to form aminoacrylate and carbamate. The carbamate hydrolyzes spontaneously, thereby releasing one of the nitrogen atoms of the pyrimidine ring as ammonia and one of its carbon atoms as CO2. (Z)-3-ureidoacrylate + H(+) + H2O = (Z)-3-aminoacrylate + CO2 + NH4(+) (Z)-3-ureidoacrylate + H2O = (Z)-3-aminoacrylate + carbamate + H(+) (Z)-2-methylureidoacrylate + H(+) + H2O = (Z)-2-methylaminoacrylate + CO2 + NH4(+) Up-regulated by the nitrogen regulatory protein C (NtrC also called GlnG) and repressed by RutR. Belongs to the isochorismatase family. RutB subfamily.