3-carboxy-cis,cis-muconate cycloisomerase

In enzymology, a 3-carboxy-cis,cis-muconate cycloisomerase (EC 5.5.1.2) is an enzyme that catalyzes the chemical reaction

2-carboxy-2,5-dihydro-5-oxofuran-2-acetate ${\displaystyle \rightleftharpoons }$ cis,cis-butadiene-1,2,4-tricarboxylate

Hence, this enzyme has one substrate, 2-carboxy-2,5-dihydro-5-oxofuran-2-acetate, and one product, cis,cis-butadiene-1,2,4-tricarboxylate.

This enzyme belongs to the family of isomerases, specifically intramolecular lyases. The systematic name of this enzyme class is 2-carboxy-2,5-dihydro-5-oxofuran-2-acetate lyase (decyclizing). Other names in common use include beta-carboxymuconate lactonizing enzyme, and 3-carboxymuconolactone hydrolase. This enzyme participates in benzoate degradation via hydroxylation.

Structural studies

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 1Q5N.

References

• Ornston LN (August 1966). "The conversion of catechol and protocatechuate to beta-ketoadipate by Pseudomonas putida. II. Enzymes of the protocatechuate pathway". The Journal of Biological Chemistry. 241 (16): 3787–94. doi:10.1016/S0021-9258(18)99840-6. PMID 5916392.
• Ornston LN (1970). "Conversion of catechol and protocatechuate to β-ketoadipate (Pseudomonas putida)". Conversion of catechol and protocatechuate to beta-ketoadipate (Pseudomonas putida). Methods Enzymol. Vol. 17A. pp. 529–549. doi:10.1016/0076-6879(71)17237-0. ISBN 978-0-12-181874-6.