Plant lipoxygenase may be involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence or responses to wounding. With linoleate as substrate, L-1 shows a preference for carbon 13 as the site for hydroperoxidation (in contrast to L-2 and L-3, which utilize either carbon 9 or 13). At pH above 8.5, only (9Z,11E,13S)-13-hydroperoxyoctadeca-9,11-dienoate is produced, but as the pH decreases, the proportion of (9S)-hydroperoxide increases linearly until at pH 6.0 it represents about 25 % of the products. (9Z,12Z)-octadecadienoate + O2 = (13S)-hydroperoxy-(9Z,11E)-octadecadienoate (9Z,12Z,15Z)-octadecatrienoate + O2 = (13S)-hydroperoxy-(9Z,11E,15Z)-octadecatrienoate (4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate + O2 = (17S)-hydroperoxy-(4Z,7Z,10Z,13Z,15E,19Z)-docosahexaenoate (4Z,7Z,10Z,13Z,16Z)-docosapentaenoate + O2 = (17S)-hydroperoxy-(4Z,7Z,10Z,13Z,15E)-docosapentaenoate (7Z,10Z,13Z,16Z,19Z)-docosapentaenoate + O2 = 17-hydroperoxy-(7Z,10Z,13Z,15E,19Z)-docosapentaenoate Binds 1 Fe cation per subunit. Iron is tightly bound. Inactive below pH 6.0. Lipid metabolism; oxylipin biosynthesis. Monomer. The hydroperoxide product serves to activate the resting enzyme. The activation is accompanied by the oxidation of Fe(2+)entadiene structure. L-1 prefers anionic substrate. Soybean contains at least 4 distinct isoenzymes, L-1, L-2, L-3a and L-3b in dry seeds, and at least two distinct isozymes in the hypocotyl/radicle region of the seedling stem. Belongs to the lipoxygenase family.