. "Catalysis of the reaction: (S)-dihydroorotate + fumarate = orotate + succinate." . . "dihydroorotate dehydrogenase activity" . "dihydroorotate oxidase activity" . "dihydoorotic acid dehydrogenase activity" . "dihydroorotate oxidase (fumarate) activity" . "DHOD activity" . "DHOdase activity" . "DHodehase activity" . .