4 hydroxyphenylacetate decarboxylase

In enzymology, a 4-hydroxyphenylacetate decarboxylase (EC 4.1.1.83) is an enzyme that catalyzes the chemical reaction

Thus, the two substrates of this enzyme are 4-hydroxyphenylacetate and H⁺, whereas its two products are 4-methylphenol and CO₂.

This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is 4-(hydroxyphenyl)acetate carboxy-lyase (4-methylphenol-forming). Other names in common use include p-hydroxyphenylacetate decarboxylase, p-Hpd, 4-Hpd, and 4-hydroxyphenylacetate carboxy-lyase.