In enzymology, a phenylpyruvate decarboxylase (EC 4.1.1.43) is an enzyme that catalyzes the chemical reaction In enzymology, a phenylpyruvate decarboxylase (EC 4.1.1.43) is an enzyme that catalyzes the chemical reaction Hence, this enzyme has one substrate, phenylpyruvate, and two products, phenylacetaldehyde 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 phenylpyruvate carboxy-lyase (phenylacetaldehyde-forming). This enzyme is also called phenylpyruvate carboxy-lyase. 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.