Enzyme reactions with phenolic compounds: formation of hydroxystyrenes through the decarboxylation of 4-hydroxycinnamic acids by Aerobacter.

A constitutive enzyme present in strains of Aerobacter has been found to decarboqdate phenylacrylic (cinnamic) acids possessing a 4-hydroxy group to the corresponding hydroxystyrenes nonoxidatively. Two such products, 4-hydroxystyrene (4-vinylphenol) and 3 ,Cdihydroxystyrene (4-vinylcatechol) from p-coumaric and caffeic acids, respectively, were purified and identified. Only 4-hydroxystyrene has been previously reported from natural sources as a rare constituent of some higher plants (1, 2). The decarboxylative enzyme, tentatively called 4-hydroxycinnamic decarboxylase on the basis of its specificity, has been extracted, and some properties of the intracelhllar and solubilized enzyme are described.