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.
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Selmer T, Andrei PI (2001). "p-Hydroxyphenylacetate decarboxylase from Clostridium difficile. A novel glycyl radical enzyme catalysing the formation of p-cresol". Eur. J. Biochem.268 (5): 1363–72. doi:10.1046/j.1432-1327.2001.02001.x. PMID11231288.
Andrei PI, Pierik AJ, Zauner S, Andrei-Selmer LC, Selmer T (2004). "Subunit composition of the glycyl radical enzyme p-hydroxyphenylacetate decarboxylase. A small subunit, HpdC, is essential for catalytic activity". Eur. J. Biochem.271 (11): 2225–30. doi:10.1111/j.1432-1033.2004.04152.x. PMID15153112.