Binds Fe2+. The enzyme from mammals accepts a range of hydroperoxyicosatetraenoates producing one or several different hydroxyepoxyicosatrienoates. The human enzyme has highest activity with (12R)-HPETE producing (5Z,8R,9E,11R,12R,14Z)-8-hydroxy-11,12-epoxyicosa-5,9,14-trienoate, followed by (12S)-HPETE producing (5Z,8Z,10R,11S,12S,14Z)-10-hydroxy-11,12-epoxyicosa-5,8,14-trienoate and (5Z,8R,9E,11S,12S,14Z)-8-hydroxy-11,12-epoxyicosa-5,9,14-trienoate . The mouse enzyme has highest activity with (8S)-HPETE, producing (5Z,8S,9S,10R,11Z,14Z)-10-hydroxy-8,9-epoxyicosa-5,11,14-trienoate . The enzymes also have the activity of EC 126.96.36.199, hydroperoxy icosatetraenoate dehydratase.