Abstract
Lipoxygenases (LOXs) are nonheme, nonsulfur iron dioxygenases that react on fatty acid substrates. Products of LOX pathway in plants have several diverse functions such as signaling in wounding and pathogen attack. In this study we aimed to clarify the physiological function of LOXs in moss. For this purpose, we isolated genes which were homologous with lipoxygenase genes and characterized them.
We have identified three candidate LOX genes from EST libraries of Marchantia polymorpha L. Full-length genes were isolated by 5'- and 3'-RACE methods and their nucleotide sequences were determined. Each gene was constituted of 2,868, 2,958, and 2,868 base pairs, and named MpLOX1, MpLOX2, and MpLOX3, respectively. To characterize MpLOX3, a recombinant MpLOX3 protein was prepared by E.coli expression system. Reaction products of MpLOX3 with fatty acid substrates were identified by LC/MS/MS. It was suggested that eicosapentaenoic and arachidonic acids were preferable as a substrate. We also found a significant 15-LOX activity in MpLOX3. This study was supported by a grant from the Research and Development Program for New Bio-industry Initiatives.
