Cytochrome P450 of the CYP74A subfamily involved in the biosynthesis of jasmonic acid from lipoxygenase-derived hydroperoxides of free fatty acids. Catalyzes the synthesis of unstable allene oxide, which is further converted spontaneously by hydrolysis or cyclization. Can use 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid (13-HPOT) and 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid (13-HPOD) as substrates. (13S)-hydroperoxy-(9Z,11E,15Z)-octadecatrienoate = (9Z,13S,15Z)-12,13-epoxyoctadeca-9,11,15-trienoate + H2O Expressed in flowers. Detected in stems and roots, but not in leaves and fruits under non-inducing conditions. Up-regulated by wounding, elicitors, methyl jasmonate or 12-oxophytodienoic acid (PDA). Belongs to the cytochrome P450 family.