ReviewLipoxygenases – Structure and reaction mechanismAlexandra Andreou, Ivo Feussner*Georg-August-University, Albrecht-von-Haller-Institute for Plant Science, Department of Plant Biochemistry, D-37077 Göttingen, Germanya r t i c l ei n f oArticle history:Received 5 March 2009Received in revised form 13 May 2009Available online 18 September 2009Keywords:DioxygenasesFatty acid peroxidationLipid peroxidationOctadecanoidsStereo- and regio-specific dioxygenationSubstrate specificitya b s t r a c tLipid oxidation is a common metabolic reaction in all biological systems, appearing in developmentallyregulated processes and as response to abiotic and biotic stresses. Products derived from lipid oxidationprocesses are collectively named oxylipins. Initial lipid oxidation may either occur by chemical reactionsor is derived from the action of enzymes. In plants this reaction is mainly catalyzed by lipoxygenase(LOXs) enzymes and during recent years analysis of different plant LOXs revealed insights into theirenzyme mechanism. This review aims at giving an overview of concepts explaining the catalytic mech-anism of LOXs as well as the different regio- and stereo-specificities of these enzymes.? 2009 Elsevier Ltd. All rights reserved.Contents1.2.Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1504LOX enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15042.1.Regio-specificity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15052.2.Stereo-specificity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1509Perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1509Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1509References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15093.1. IntroductionFatty acids, major building blocks of lipids, are major compo-nents of membranes and storage lipids. Apart from the turnoverof fatty acids within lipids and their use as carbon and energysource, oxidation of unsaturated fatty acids is a major reaction inlipid metabolism (Feussner and Wasternack, 2002). The formationof fatty acid hydroperoxides may occur either by chemical oxida-tion or by the action of enzymes such as lipoxygenase (LOX) (And-reou et al., 2009b; Mosblech et al., 2009). The metabolites thatderive from oxidation of polyunsaturated fatty acids (PUFAs) viaa LOX-catalyzed step as well as those metabolites that derive fromalternative oxidation reactions and subsequent reactions are col-lectively named oxylipins and the metabolic pathways involvedin oxylipin formation are collectively called oxylipin pathway. Ina number of reviews the diversity of oxylipins, the enzymes in-volved in their formation as well as their physiological functionin non-mammals has been summarized (i.e., Andreou et al.,2009b; Blée, 2002; Gerwick et al., 1999; Howe and Jander, 2008;Liavonchanka and Feussner, 2006; Mosblech et al., 2009; Oliw,2002; Pohnert, 2005; Schneider et al., 2007b; Stumpe and Feuss-ner, 2006; Tsitsigiannis and Keller, 2007; Wasternack, 2007). Re-cent genome sequences shed new light on the structure andreaction mechanism of LOXs. Consequently, our knowledge aboutLOXs in an increasing number of organisms has been substantiatedand new aspects are reviewed here.2. LOX enzymesLOXs are a family of non-heme iron containing dioxygenases(Brash, 1999; Schneider et al., 2007b). They catalyze the insertion0031-9422/$ - see front matter ? 2009 Elsevier Ltd. All rights reserved.doi:10.1016/j.phytochem.2009.05.008Abbreviations: HPODE, hydroperoxy octadecadienoic acid; LA, linoleic acid; LOX,lipoxygenase; PUFA, polyunsaturated fatty acid.* Corresponding author. Tel.: +49 551 395743; fax: +49 551 395749.E-mail address: ifeussn@unigoettingen.de (I. Feussner).Phytochemistry 70 (2009) 1504–1510Contents lists available at ScienceDirectPhytochemistryjournal homepage: www.elsevier.com/locate/phytochem
