Decarboxylates OPET (5-oxo-pent-3-ene-1,2,5- tricarboxylic acid) into HHDD (2-hydroxy-hept-2,4-diene-1,7- dioate) and isomerizes it to OHED (2-oxo-hept-3-ene-1,7-dioate). 5-carboxymethyl-2-hydroxymuconate Delta-isomerase Homoprotocatechuate catabolism bifunctional isomerase/decarboxylase 5-carboxymethyl-2-oxo-hex-3-ene-1,7-dioate decarboxylase 2-hydroxyhepta-2,4-diene-1,7-dioate isomerase hpcE 427 MKGTIFAVALNHRSQLDAWQEAFQQSPIKAPPKTAVWFIKPRNTVIGCGEPIPFPQGENLLSGATVALIVGKTATKVREEDAAEYIAGYALANDVSLPEESFYRPAIKAKCRDGFCPIGETVALSNVDNLTIYTEINGRPADHWNTSDLQRNAAQLLSALSEFATLNPGDAILLGTPQARVEIQPGDRVRVLAEGFPPLENPVVDEREVTTRKSFPTLPHPHGTLFALGLNYADHASELEFKPPEEPLVFLKAPNTLTGDNQTSVRPNNIEYMHYEAELVVVIGKQARNVSEADAMDYVAGYTVCNDYAIRDYLENYYRPNLRVKSRDGLTPMLSTIVPKEAIPDPHNLTLRTFVNGELRQQGTTADLIFSVPFLIAYLSEFMTLNPGDMIATGTPKGLSDVGDEVVVEVEGVGRLVNRIVSEETAK HPCE_ECOLX 5-oxopent-3-ene-1,2,5-tricarboxylate decarboxylase