The enzyme phenylpyruvate decarboxylase (EC 4.1.1.43) catalyzes the chemical reaction

phenylpyruvate phenylacetaldehyde + 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 phenylpyruvate carboxy-lyase (phenylacetaldehyde-forming). This enzyme is also called phenylpyruvate carboxy-lyase.^{[citation needed]} This enzyme participates in phenylalanine and tryptophan metabolism.

As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code 2NXW.

• Asakawa T, Wada H, Yamano T (1968). "Enzymatic conversion of phenylpyruvate to phenylacetate". Biochim. Biophys. Acta. 170 (2): 375–91. doi:10.1016/0304-4165(68)90017-2. PMID 4303395.