The enzyme is involved in the catechol?meta-cleavage pathway, a major mechanism for degradation of aromatic compounds. Also acts, more slowly, on?cis-2-oxohex-4-enoate, but not on the?trans-isomer. The enzyme was named when it was thought that the substrate is 2-oxopent-4-enoate. However, it was later found that the actual substrate is its tautomer (2Z)-2-hydroxypenta-2,4-dienoate. In some organisms the enzyme forms a complex with EC?4.1.1.77, 2-oxo-3-hexenedioate decarboxylase (previously named 4-oxalocrotonate decarboxylase).
