Lipoxygenase
Lipoxygenases (EC 1.13.11.-) (LOX) are a family of (non-heme) iron-containing enzymes most of which catalyze the dioxygenation of polyunsaturated fatty acids in lipids containing a cis,cis-1,4-pentadiene into cell signaling agents that serve diverse roles as autocrine signals that regulate the function of their parent cells, paracrine signals that regulate the function of nearby cells, and endocrine signals that regulate the function of distant cells.
| Lipoxygenase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Structure of rabbit reticulocyte 15S-lipoxygenase. | |||||||||
| Identifiers | |||||||||
| Symbol | Lipoxygenase | ||||||||
| Pfam | PF00305 | ||||||||
| InterPro | IPR013819 | ||||||||
| PROSITE | PDOC00077 | ||||||||
| SCOP2 | 2sbl / SCOPe / SUPFAM | ||||||||
| OPM superfamily | 80 | ||||||||
| OPM protein | 2p0m | ||||||||
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The lipoxygenases are related to each other based upon their similar genetic structure and dioxygenation activity. However, one lipoxygenase, ALOXE3, while having a lipoxygenase genetic structure, possesses relatively little dioxygenation activity; rather its primary activity appears to be as an isomerase that catalyzes the conversion of hydroperoxy unsaturated fatty acids to their 1,5-epoxide, hydroxyl derivatives.
Lipoxygenases are found in eukaryotes (plants, fungi, animals, protists); while the third domain of terrestrial life, the archaea, possesses proteins with a slight (~20%) amino acid sequence similarity to lipoxygenases, these proteins lack iron-binding residues and therefore are not projected to possess lipoxygenase activity.