Koeduka Takao, Stumpe Michael, Matsui Kenji, Kajiwara Tadahiko, Feussner Ivo
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yoshida 1677-1, Yamaguchi, 753-8515, Japan.
Lipids. 2003 Nov;38(11):1167-72. doi: 10.1007/s11745-003-1175-9.
The cDNA from barley coding FA hydroperoxide lyase (HPL) was cloned. A recombinant protein derived from the cDNA was expressed in Escherichia coli as an active enzyme. Thus far, there have been no reports on HPL in monocotyledonous plants. The recombinant protein was shown to be most active to linolenic acid 13-hydroperoxide, followed by linoleic acid 13-hydroperoxide. 9-Hydroperoxides of the FA could not be substrates for the recombinant HPL. The activity was dramatically enhanced in the presence of a detergent and/or a salt in the reaction mixture. At the same time, the kinetics of the reaction, including inactivation and the Vmax value of the HPL, were also greatly modulated, depending on the concentration of a monovalent cation and/or a detergent in the reaction mixture. These results suggest that these effectors induced a conformational change in barley HPL, resulting in an improvement in substrate binding and in enzyme activity.
克隆了来自大麦的编码脂肪酸氢过氧化物裂解酶（HPL）的cDNA。从该cDNA衍生的重组蛋白在大肠杆菌中作为活性酶表达。到目前为止，尚无关于单子叶植物中HPL的报道。该重组蛋白对亚麻酸13-氢过氧化物活性最高，其次是亚油酸13-氢过氧化物。脂肪酸的9-氢过氧化物不能作为重组HPL的底物。在反应混合物中存在去污剂和/或盐时，活性显著增强。同时，反应动力学，包括HPL的失活和Vmax值，也根据反应混合物中单价阳离子和/或去污剂的浓度而受到极大调节。这些结果表明，这些效应物诱导了大麦HPL的构象变化，从而改善了底物结合和酶活性。
