关键词: 脂氧合酶, 晶体结构, 氧化活性

Abstract: A novel lipoxygenase model compound, Cl·3CH₃CH₂OH·H₂O was synthesized and characterized(CTBN,N,N',N'-tetrakis(2'-benzimidazolylmethyl)-ortho-diamine trans-cyclohexane). The single crystal X-ray analysis shows that this compound crystallizes in the monoclinic system, space group P2₁/n with cell parameters a=1.129 38(7) nm, b=1.490 04(9) nm, c=2.693 46(17) nm, β=9.195 30(10)°, V=4.530 0(5) nm³, and Z=4; R=0.060 2, wR=0.162 9. It is interesting that the iron(Ⅱ) ion is bonded to three benzimidazolyl nitrogens(the average bond distance of Fe_N is 0.206 4 nm) and two amino nitrogens(the bond distances of Fe_N are 0.218 9 and 0.229 1 nm, respectively) of ligand CTB, there is an uncoordinating benzimidazolyl group expanding in the space, the sixth position is coordinated by one chloride ion(the bond length of Fe_Cl is 0.237 25 nm). So the title complex shows a distortedly octahedral coordination. Following the reaction of oxidative products with thiobabituric acid indicates that the complex can enhance linoleic acid oxidation. Electrospray ionization mass-spectrum in positive ion mode(ESI+) shows that linoleic acid is oxidatively cleft resulting in volatile small molecular fragments, such as malondialdehyde, nonanal, nonenal, malonic acid, hydroxy ethanal and nonanal acid, etc. These aldehydes and ω-oxo acids are important phytoalexins, which can induce biosynthesis of numerous compounds, proteins and enzymes in physiological and pathological signaling systems.

Key words: Lipoxygenase, Crystal structure, Oxidative activity