hydro-lyase activity 4-oxalmesaconate hydratase activity https://github.com/geneontology/go-ontology/issues/30193 Catalysis of the reaction: 2-hydroxy-4-oxobutane-1,2,4-tricarboxylate = (1E)-4-oxobut-1-ene-1,2,4-tricarboxylate + H2O. GO:0047584 MetaCyc:RXN-2463 4-carboxy-2-oxohexenedioate hydratase activity 4-carboxy-2-oxobutane-1,2,4-tricarboxylate 2,3-hydro-lyase activity RHEA:17401 molecular_function 2-hydroxy-4-oxobutane-1,2,4-tricarboxylate 2,3-hydro-lyase [(E)-4-oxobut-1-ene-1,2,4-tricarboxylate-forming] 2-hydroxy-4-oxobutane-1,2,4-tricarboxylate 2,3-hydro-lyase activity gamma-oxalmesaconate hydratase activity EC:4.2.1.83 oxalmesaconate hydratase activity KEGG_REACTION:R04478