In enzymology, a phenylacetaldehyde dehydrogenase () is an enzyme that catalyzes the chemical reaction phenylacetaldehyde + NAD+ + H2O phenylacetate + NADH + 2 H+ The 3 substrates of this enzyme are phenylacetaldehyde, NAD+, and H2O, whereas its 3 products are phenylacetate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is phenylacetaldehyde:NAD+ oxidoreductase. This enzyme participates in phenylalanine metabolism and styrene degradation. References EC 1.2.1 NADH-dependent enzymes Enzymes of unknown structure