Carboxymethylenebutenolidase

In enzymology, a carboxymethylenebutenolidase (, also known as CMBL and dienelactone hydrolase) is an enzyme that catalyzes the chemical reaction


 * 4-carboxymethylenebut-2-en-4-olide + H2O $$\rightleftharpoons$$ 4-oxohex-2-enedioate

Thus, the two substrates of this enzyme are 4-carboxymethylenebut-2-en-4-olide and H2O, whereas its product is 4-oxohex-2-enedioate.

This enzyme belongs to the family of hydrolases, specifically those acting on carboxylic ester bonds. The systematic name of this enzyme class is 4-carboxymethylenebut-2-en-4-olide lactonohydrolase. Other names in common use include maleylacetate enol-lactonase, dienelactone hydrolase, and carboxymethylene butenolide hydrolase. This enzyme participates in gamma-hexachlorocyclohexane degradation and 1,4-dichlorobenzene degradation.

Structural studies
As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes, , , , , , , , , and.