Kobe University Repository : Kernel

cis ,c is-Muconate cycloisomerase (MC) was purif ied to homogenei ty from benzamide-assimilat ing Arthrobacter sp. BA-5-17. The purif ied enzyme showed high act ivi t ies for cis ,c is-muconate and 3-methyl-cis ,c is-muconate, and preferred the 3-subst i tuted derivat ives over the derivat ives with the same subst i tuent a t the 2 posi t ion as a substrate . A gene encoding MC of s t rain BA-5-17 was cloned and named catB . The catB gene was clustered with catR encoding a putat ive LysR-type regulator , catC encoding a putat ive muconolactone isomerase, and catA-II encoding the catechol 1,2-dioxygenase isozymes CD-III-1 and III-2. These genes showed the same orientat ions in t ranscript ional direct ions and the organizat ion of cloned genes was catRBCA-II . In the phylogenet ic analysis of MCs and chloro-cis ,c is-muconate cycloisomerases, the BA-5-17 and Streptomyces setoni i MCs formed a subfamily, c lear ly dis t inguished from those of other MCs.