Plant lipoxygenases may be involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence or responses to wounding. Catalyzes the hydroperoxidation of lipids containing a cis,cis-1,4-pentadiene structure. Linoleic and linolenic acids are the preferred substrates, but is also active with arachidonic acid. The products are almost exclusively the S enantiomers. (9Z,12Z)-octadecadienoate + O2 = (9S)-hydroperoxy-(10E,12Z)-octadecadienoate Binds 1 Fe cation per subunit. Iron is tightly bound. Optimum pH is 5.5-7.0. Lipid metabolism; oxylipin biosynthesis. Monomer. Expressed in tubers and roots. Detected in leaves, petioles and stems. Up-regulated in stored tubers 8 hours after wounding and by jasmonate. Down-regulated in growing tubers containing already high levels of LOX1.5 at the time of wounding. Belongs to the lipoxygenase family.