The resulting 5-HPETE yields the unstable allylic epoxide substrate LTA4 which is quickly hydrolyzed by the LTA4H (leukotriene A4 hydrolase) enzyme to produce LTB4, or synthesized by LTC4S (leukotriene C4 synthase) with the addition of glutathione to produce LTC4 which can be further metabolized to produce LTD4 (leukotriene D4) and LTE4 (leukotriene E4). The lipooxygenase pathway is one of several possible pathways including the cyclooxygenase pathway (also PGH synthase pathway), isoprostane pathway, and cytochrome P450 epoxygenases pathway following the arachidonic acid metabolism, but is the only pathway in which the subsequent steps will lead to the production of leukotrienes.
The 5-HPETE intermediate gives rise to LTA4, a substrate that is rapidly converted into LTB4 by LTA4H or synthesized into LTC4 via LTC4S with glutathione addition. This process can be further metabolized into LTD4 and LTE4. The lipooxygenase pathway is one of several metabolic routes for arachidonic acid, including the cyclooxygenase pathway.