title: Metabolism of 5-chlorosubstituted muconolactones.
abstract: The stereochemistry of the four stereoforms of 5-chloro-3-methylmuconolactones could be deduced from NMR and stability data, and from the comparison with authentic (4R, 5S)-5-chloromuconolactone. Muconolactone isomerase of Alcaligenes eutrophus JMP 134 was shown to catalyze syn-elimination of hydrogen chloride from (4R, 5R)-5-chloro-3-methylmuconolactone, (4R, 5S)-5-chloro-3 -methylmuconolactone and (4R, 5S)-5-chloromuconolactone to form 3-methyl-trans-dienelactone, 3-methyl-cis-dienelactone and a 3:1 mixture of cis- and trans-dienelactone, respectively. 3-Methyl-trans-dienelactone was a substrate of pJP4-encoded dienelactone hydrolase of A. eutrophus JMP 134, whereas 3-methyl-cis-dienelactone transformation was negligible indicating a restricted substrate specificity of this enzyme. Both substrates were transformed into 3-methylmaleylacetate which in turn was a substrate for maleylacetate reductase. This compound was shown to possess a cyclic structure (4-hydroxy-3-methyl-muconolactone) under acidic conditions.
authors.affiliation: Department of Microbiology, National Research Centre for Biotechnology, Braunschweig, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Prucha
authors.forename: V
authors.initials: V
authors.lastname: Wray
authors.forename: D H
authors.initials: DH
authors.lastname: Pieper
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics; D000421:Alcaligenes / Q000201:enzymology; D001426:Bacterial Proteins; D001711:Biotransformation; D019748:Carbon-Carbon Double Bond Isomerases; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D007535:Isomerases / Q000378:metabolism; D008298:Maleates / Q000737:chemistry / Q000378:metabolism; D015394:Molecular Structure; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D008298:Maleates; C088142:5-chloromuconolactone; C011905:maleoylacetic acid; D002265:Carboxylic Ester Hydrolases; C046130:carboxymethylenebutenolidase; D007535:Isomerases; D019748:Carbon-Carbon Double Bond Isomerases; C100087:muconolactone delta-isomerase; D015107:4-Butyrolactone