Feedback activation of ferrous 5-lipoxygenase during leukotriene synthesis by coexisting linoleic acid

Journal of Lipid Research

Koichi Ueno¹  Kazunori Tsuchida²  Ichiro Koshiishi²  Tokuko Takajo² 

[1] Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan;Nihon Pharmaceutical University, 10281 Komuro, Ina-machi, Kita-Adachi-gun, Saitama, 362-0806 Japan;

关键词: isozyme;    pseudoperoxidase reaction;    hydroperoxides;   

DOI  :  

来源: DOAJ

【 摘 要 】

Ferrous lipoxygenases seem to be activated through a feedback control mechanism via FA hydroperoxides generated from PUFAs by partially existing ferric lipoxygenases. However, during leukotriene synthesis, feedback activation of ferrous 5-lipoxygenase in the presence of arachidonic acid (AA) was not observed. In the present study, we examined the feedback activation of ferrous 5-lipoxygenase in the 5-lipoxygenase/AA system in the presence of linoleic aicd (LA), which is a predominant component of membrane phospholipids. When potato 5-lipoxygenase was incubated with AA and LA in the presence of nitroxyl radical, 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrroline-N-oxyl (CmΔP), one-electron redox cycle reaction between ferric and ferrous 5-lipoxygenase was detected. For each revolution of the cycle, one molecule of PUFA and one molecule of its hydroperoxide were converted into PUFA-allyl radical-CmΔP adduct ([PUFA−H]·-CmΔP) and PUFA-epoxyallyl radical-CmΔP adduct ([PUFA−H+O]·-CmΔP), respectively. The ratios, [AA−H]·-CmΔP/[LA−H]·-CmΔP and [AA−H+O]·-CmΔP/[LA−H+O]·-CmΔP, were estimated to be 1.7 and 0.13, respectively. These facts indicate that ferrous 5-lipoxygenase is activated through feedback control in the presence of LA, and that resulting ferric 5-lipoxygenase catalyzes the stoichiometric synthesis of leukotrienes from AA. In conclusion, the biosynthesis of leukotrienes is remarkably efficient.

【 授权许可】

Unknown