Reaction catalyzed by 2-pyrone-4,6-dicarboxylate lactonase (3.1.1.57)

		+		H2O	=
	2-oxo-2H-pyran-4,6-dicarboxylate	+		H2O	=		(1E)-4-oxobut-1-ene-1,2,4-tricarboxylate