1,1′-Methide-bi-vitamin K3 (B) has been isolated as a dinaphthoquinone methide radical (DNQM) by the transformation of 1-imino(acetylhydrazino)-vitamin K3 (A). The transformation follows a biomimetic activation pathway mediated via Cu(II) ion catalyzed oxidative coupling. Single crystal X-ray and electron spin resonance (ESR) experiments combined with density functional calculations elucidate the “resonance structure” of the DNQM radical (B). Fluorescence investigations reveal that DNQM facilitates interaction with the cysteine residue. As compared to the parent substrate, B shows a depletion in the level of GSH, triggering apoptosis in HeLa cells.
通过 1-亚
氨基(乙酰
肼)-
维生素 K3(A)的转化,分离出 1,1′-甲
萘双
维生素 K3(B),作为二
萘醌甲
萘基(DNQM)。这种转化遵循一种通过 Cu(II)离子催化氧化偶联介导的仿
生物活化途径。单晶 X 射线和电子自旋共振(ESR)实验结合密度泛函计算阐明了 DNQM 自由基的 "共振结构"(B)。荧光研究表明,DNQM 促进了与半胱
氨酸残基的相互作用。与母体底物相比,B 会消耗 GSH
水平,引发 HeLa 细胞凋亡。