Requires Mn2+. The product of cycloisomerization of 3-chloro-cis,cis-muconate spontaneously eliminates chloride to produce cis-4-carboxymethylenebut-2-en-4-olide. Also acts (in the reverse direction) on 2-chloro-cis,cis-muconate. Not identical with EC 18.104.22.168 (muconate cycloisomerase) or EC 22.214.171.124 (dichloromuconate cycloisomerase).
no activity with cis,cis-muconate, 3-chloromuconate, 3-methylmuconate and 2,4-dichloromuconate, key enzyme in a modified ortho-pathway in cells utilizing 2-chlorophenol via a 3-chlorocatechol branch of a modified ortho-pathway