Seed lipoxygenases: occurrence and functions

Lipoxygenases are widely distributed in the animal and plant kingdoms. Thes e enzymes catalyse the hydroperoxidation of polyunsaturated fatty acids con taining cis,cis-1,4-pentadiene moieties. Multiple isoenzymes, with differen t biochemical properties and tissue distribution, have been described for m any plants. Lipoxygenases occur in vegetative tissues, but also accumulate in various seeds, and especially in leguminous seeds. Although several func tions have been proposed for vegetative lipoxygenases, the roles of seed li poxygenases remain enigmatic. In this review we discuss whether physiologic al functions assigned to vegetative lipoxygenases can be extended to seed i soforms.