In neutrophils, an unknown lipoxygenase may mediate hydrogen abstraction from 17(S)-hydroperoxy-docosapentaenoic acid (17(S)-Hp-DPAn-3) to form 16(S),17(S)-epoxy-docosapentaenoic acid (16(S),17(S)-epoxy-DPAn-3) (Dalli et al. 2013). If, as assumed, DPA metabolism follows the same path as DHA metabolism, the lipoxygenase could be the dual-functional 5-lipoxygenase (ALOX5). The formation of this epoxy intermediate is supported by chemical synthesis experiments (Aursnes et al. 2014, Primdahl et al. 2017).