Catalysis of the reaction: (S)-2-(5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamido)succinate = fumarate + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxamide.
Statements about (S)-2-(5-Amino-1-(5-Phospho-D-Ribosyl)imidazole-4-Carboxamido) Succinate Lyase (Fumarate-Forming) Activity