1.13.11.60 cytochrome P450 PpoA contains a high spin ferriheme. PpoA uses different heme domains to catalyze two separate reactions. Within the N-terminal heme peroxidase domain, linoleic acid is oxidized to (8R,9Z,12Z)-8-hydroperoxy-9,12-octadecadienoate by abstracting a H-atom from C-8 of the fatty acid, yielding a carbon-centered radical that reacts with molecular dioxygen. In the second reaction step, (8R,9Z,12Z)-8-hydroperoxy-9,12-octadecadienoate is isomerized within the C-terminal P450 heme thiolate domain to (5S,8R,9Z,12Z)-5,8-dihydroxy-9,12-octadecadienoate 1.13.11.60 heme - 1.13.11.60 heme ferric hemeprotein 1.13.11.60 heme hemoptotein 1.13.11.60 heme PpoA contains a high spin ferriheme. PpoA uses different heme domains to catalyze two separate reactions. Within the N-terminal heme peroxidase domain, linoleic acid is oxidized to (8R)-hydroperoxyoctadecadienoic acid by abstracting a H-atom from C-8 of the fatty acid, yielding a carbon-centered radical that reacts with molecular dioxygen. In the second reaction step, 8-hydroperoxyoctadecadienoic acid is isomerized within the C-terminal P450 heme thiolate domain to 5,8-dihydroxyoctadecadienoic acid 1.13.11.60 heme the enzyme contains at least 2 mol of heme/mol of enzyme