title: Stereo- and regiospecific cis,cis-muconate cycloisomerization by Rhodococcus rhodochrous N75.
abstract: cis,cis-Muconate cycloisomerase was purified to homogeneity from cells of Rhodococcus rhodochrous N75 grown at the expense of benzoate and p-toluate as the sole sources of carbon. A single cycloisomerase was found to be induced in this organism with no isoforms being detected when R. rhodochrous N75 was grown on either benzoate or p-toluate as the sole source of carbon. The enzyme is hexameric with a single subunit Mr of 40,000. cis,cis-Muconate cycloisomerase from R. rhodochrous N75 displayed strict regio- and stereospecificity whereby cis,cis-muconate is cycloisomerized to (4S)-muconolactone and 2-methyl- and 3-methyl-substituted muconates are cycloisomerized to 2-methyl- and 4-methyl-substituted muconolactones by 1,4- and 3,6-cycloisomerization, respectively.
authors.affiliation: Institute of Biotechnology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QT, UK. ccha@snu.ac.kr
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Cha
authors.forename: Neil C
authors.initials: NC
authors.lastname: Bruce
mesh_terms: D000595:Amino Acid Sequence; D006863:Hydrogen-Ion Concentration; D019753:Intramolecular Lyases / Q000378:metabolism*; D007536:Isomerism; D007700:Kinetics; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012240:Rhodococcus / Q000201:enzymology*; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: C005939:muconic acid; D019753:Intramolecular Lyases; C021811:muconate cycloisomerase; D013011:Sorbic Acid