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, 5S)-5-chloro-3-methylmuconolactone, (4R, 5S)-5-chloro-3-methyl-muconolactone and (4R, 5S)-5-chloromuconolactone to form 3-methyl-cis -dienelactone, 3-methyl-trans -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-methylmuconolactone) under acidic conditions.

This publication has 53 references indexed in Scilit: