- Plant phenylacetaldehyde synthase is a bifunctional homotetrameric enzyme that catalyzes phenylalanine decarboxylation and oxidation. Kaminaga, Y., Schnepp, J., Peel, G., Kish, C.M., Ben-Nissan, G., Weiss, D., Orlova, I., Lavie, O., Rhodes, D., Wood, K., Porterfield, D.M., Cooper, A.J., Schloss, J.V., Pichersky, E., Vainstein, A., Dudareva, N. J. Biol. Chem. (2006)