Involved in the anaerobic catabolism of ethylbenzene by denitrifying bacteria. Ethylbenzene is the preferred substrate; the enzyme from some strains oxidizes propylbenzene, 1-ethyl-4-fluorobenzene, 3-methylpent-2-ene and ethylidenecyclohexane. Toluene is not oxidized. p-Benzoquinone or ferrocenium can act as electron acceptor. Contains molybdopterin, [4Fe-4S] clusters and heme b.