text: Ferulic acid decarboxylases (Fdc) are decarboxylase enzymes capable of the reversible decarboxylation of aromatic carboxylic acids such as ferulic acid and cinnamic acid. Fdcs are fungal homologues of the E.coli' UbiD enzyme  which is involved in ubiquinone biosynthesis. This places Fdc within the wider UbiD enzyme family, representing a  distinct clade within the family 
  Presence of fdc1 and the associated pad1 genes (Pad1 homologous to UbiX in E.coli) were shown to be required for the decarboxylation of phenylacrylic acids in Saccharomyces cerevisiae.
  In 2015 the cofactor prFMN was discovered in the active site of Fdc1 from Aspergillus niger (AnFdc) by crystallography, prior to this genetic studies had led to the assumption that both UbiD and UbiX encoded isofunctional decarboxylases. In actuality UbiX/Pad were found to be flavin preyltransferases supplying the prFMN cofactor to UbiD/Fdc where it is utilised for the reversible decarboxylation of alpha-beta unsaturated carboxylic acid substrates. Since the discovery of prFMN AnFDC has become the most well understood representative of the UbiD enzyme family