Catalyzes the dioxygenation of linoleic acid to (8R)-hydroperoxylinoleate and isomerization of the resulting hydroperoxide to (7S,8S)-dihydroxylinoleate. (9Z,12Z)-octadecadienoate + O2 = (8R,9Z,12Z)-8-hydroperoxyoctadeca-9,12-dienoate (8R,9Z,12Z)-8-hydroperoxyoctadeca-9,12-dienoate = (7S,8S,9Z,12Z)-7,8-dihydroxyoctadeca-9,12-dienoate Optimum pH is 7.2-7.4. Homotetramer. The N-terminus is blocked. Belongs to the peroxidase family.