RESUMO
Lipoxygenases are widespread plant enzymes that catalyze the peroxidation of polyunsaturated fatty acids. This reaction is pivotal in the enzymatic cascade that leads to production of numerous metabolism regulators named oxylipins. The activity of these biologically active substances is directly associated with defence reactions in conditions of biotic and abiotic stresses as well as with the regulation of plant growth, propagation and senescence. In this review the contemporary notions about lipoxygenases classification, structure and catalytic properties are summarized. The features of enzyme activity regulation by transcriptional and posttranslational mechanisms in addition to the role of lipoxygenase catalysis in plant cell signalling are discussed.
Assuntos
Regulação da Expressão Gênica de Plantas , Lipoxigenases/metabolismo , Oxilipinas/metabolismo , Células Vegetais/enzimologia , Proteínas de Plantas/metabolismo , Plantas/enzimologia , Adaptação Fisiológica , Peroxidação de Lipídeos , Lipoxigenases/química , Lipoxigenases/genética , Modelos Moleculares , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas/genética , Processamento de Proteína Pós-Traducional , Transdução de Sinais , Estresse Fisiológico , Transcrição GênicaRESUMO
Phospholipase D (PLD) catalyzes hydrolysis of phospholipids with production of phosphatidic acid, which often acts as secondary messenger of transduction of intracellular signals. This review summarizes data of leading laboratories on specific features of organization and regulation of PLD activity in plant and animal cells. The main structural domains of PLD (C2, PX, PH), the active site, and other functionally important parts of the enzyme are discussed. Regulatory mechanisms of PLD activity are characterized in detail. Studies associated with molecular design, analysis, and synthesis of new nontoxic substances capable of inhibiting different PLD isoenzymes in vivo are shown to be promising for biotechnology and medicine.
