Linoleate 9S-lipoxygenase (, 9-lipoxygenase, 9S-lipoxygenase, linoleate 9-lipoxygenase, LOX1 (gene), 9S-LOX) is an enzyme with systematic name linoleate:oxygen 9S-oxidoreductase. This enzyme catalyses the following chemical reaction
Linoleate 9S-lipoxygenase contains nonheme iron.