METABOLISM OF 2-CHLORO-4-METHYLPHENOXYACETATE BY ALCALIGENES-EUTROPHUS JMP-134

2-Chloro-4-methylphenoxyacetate is not a growth substrate for Alcalige nes eutrophus JMP 134 and JMP 134-1. It is, however, being transformed by enzymes of 2,4-dichlorophenoxyacetic acid metabolism to 2-chloro-4 -methyl-cis,cis-muconate, which is converted by enzymatic 1,4-cycloiso merization to 4-carboxymethyl-2-chloro-4-methylmuconolactone as a dead end metabolite. Chemically, only 3,6-cycloisomerization occurs, givin g rise to both diastereomers of 4-carboxychloromethyl-3-methylbut-2-en -4-olide. Those lactones harboring a chlorosubstituent on the 4-carbox ymethyl side chain were surprisingly stable under physiological as wel l as acidic conditions.