Butenko Nataliya, Pinheiro José Paulo, Da Silva José Paulo, Tomaz Ana Isabel, Correia Isabel, Ribeiro Vera, Costa Pessoa João, Cavaco Isabel
Departamento de Química e Farmácia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais, 1049-001 Lisboa, Portugal.
Departamento de Química e Farmácia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
J Inorg Biochem. 2015 Jun;147:165-76. doi: 10.1016/j.jinorgbio.2015.04.010. Epub 2015 Apr 25.
The nuclease activity of VO(acac)2 (1, acac = acetylacetone) and its derivatives VO(hd)2 (2, hd = 3,5-heptanedione), VO(Cl-acac)2 (3, Cl-acac = 3-chloro-2,4-pentanedione), VO(Et-acac)2 (4, Et-acac = 3-ethyl-2,4-pentanedione) and VO(Me-acac)2 (5, Me-acac = 3-methyl-2,4-pentanedione), is studied by agarose gel electrophoresis, UV-visible spectroscopy, cyclic and square wave voltammetry and (51)V NMR. The mechanism is shown to be oxidative and associated with the formation of reactive oxygen species (ROS). Hydrolytic cleavage of the phosphodiester bond is also promoted by 1, but at much slower rate which cannot compete with the oxidative mechanism. The generation of ROS is much higher in the presence of phosphate buffer when compared with organic buffers and this was attributed to the formation of a mixed-ligand complex containing phosphate, (V(IV)O)(V(V)O)(acac)2(HnPO4(n-3)), presenting a quasi-reversible voltammetric behavior. The formation of this species was further observed by Electrospray Ionization Mass Spectrometry (ESI-MS). Phosphate being an essential species in most biological media, the importance of the formation of mixed-ligand species in other vanadium systems is emphasized.
通过琼脂糖凝胶电泳、紫外可见光谱、循环伏安法和方波伏安法以及钒 - 51核磁共振研究了二乙酰丙酮氧钒（1，acac = 乙酰丙酮）及其衍生物二（3,5 - 庚二酮）氧钒（2，hd = 3,5 - 庚二酮）、二（3 - 氯 - 2,4 - 戊二酮）氧钒（3，Cl - acac = 3 - 氯 - 2,4 - 戊二酮）、二（3 - 乙基 - 2,4 - 戊二酮）氧钒（4，Et - acac = 3 - 乙基 - 2,4 - 戊二酮）和二（3 - 甲基 - 2,4 - 戊二酮）氧钒（5，Me - acac = 3 - 甲基 - 2,4 - 戊二酮）的核酸酶活性。结果表明其作用机制是氧化作用，并与活性氧（ROS）的形成有关。1也能促进磷酸二酯键的水解断裂，但速率要慢得多，无法与氧化机制竞争。与有机缓冲液相比，在磷酸盐缓冲液存在下ROS的生成量要高得多，这归因于形成了一种含磷酸盐的混合配体配合物(V(IV)O)(V(V)O)(acac)2(HnPO4(n - 3))，呈现出准可逆伏安行为。通过电喷雾电离质谱（ESI - MS）进一步观察到了该物种的形成。由于磷酸盐是大多数生物介质中的必需成分，因此强调了在其他钒体系中形成混合配体物种的重要性。
