InterPro domain: IPR036226

Lipoxygenases ([intenz:1.13.11.-]) are a class of iron-containing dioxygenases which catalyses the hydroperoxidation of lipids, containing a cis,cis-1,4-pentadiene structure. They are common in plants where they may be involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence or responses to wounding. In mammals a number of lipoxygenases isozymes are involved in the metabolism of prostaglandins and leukotrienes [ 1 ]. Sequence data is available for the following lipoxygenases:

• Plant lipoxygenases ( 1.13.11.12 ). Plants express a variety of cytosolic isozymes as well as what seems to be a chloroplast isozyme [ 2 ].
• Mammalian arachidonate 5-lipoxygenase ( 1.13.11.34 ).
• Mammalian arachidonate 12-lipoxygenase ( 1.13.11.31 ).
• Mammalian arachidonate 15-lipoxygenase B (also known as erythroid cell-specific 15-lipoxygenase; 1.13.11.33 ).

The iron atom in lipoxygenases is bound by four ligands, three of which arehistidine residues [ 3 ]. Six histidines are conserved in all lipoxygenase sequences, five of them are found clustered in a stretch of 40 amino acids. This region contains two of the three iron-ligands; the other histidines have been shown [ 4 ] to be important for the activity of lipoxygenases.

1. Arachidonic acid metabolism. Annu. Rev. Biochem. 55, 69-102
2. A novel lipoxygenase from rice. Primary structure and specific expression upon incompatible infection with rice blast fungus. J. Biol. Chem. 269, 3755-61
3. The three-dimensional structure of an arachidonic acid 15-lipoxygenase. Science 260, 1482-6
4. Conserved histidine residues in soybean lipoxygenase: functional consequences of their replacement. Biochemistry 31, 4053-7