This 3-hydroxyacyl-CoA dehydrogenase is involved in the degradation of phenylacetic acid, presumably in steps following the opening of the phenyl ring. The sequences included in this model are all found in aparrent operons with other related genes such as paaA, paaB, paaD, paaE, paaF and paaN. Some genomes contain these other genes without an apparent paaC in the same operon - possibly in these cases a different dehydrogenase involved in fatty acid degradation may fill in the needed activity. This enzyme has domains which are members of the pfam02737 and pfam00725 families.