Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, H-4010 Debrecen, Hungary.
Department of Inorganic and Analytical Chemistry, University of Debrecen, P.O. Box 21, H-4010 Debrecen, Hungary; Gedeon Richter Plc, PO Box 27, Budapest, 10, H-1475, Hungary(1).
J Inorg Biochem. 2017 Dec;177:198-210. doi: 10.1016/j.jinorgbio.2017.08.033. Epub 2017 Sep 30.
The results of electrochemical and SOD activity measurements of such copper(II) complexes of terminally protected multihistidine peptides that may mimic the active site of CuZnSOD enzyme are submitted and completed with solution equilibrium studies of some copper(II)-ligand systems. The equilibrium data confirm that the thermodynamic stabilities increase with the increasing number of histidyl residues in the amino acid sequence, the stability order, however, can be finely tuned by the number and quality of amino acids between histidine residues. Based on the cyclic voltammetric studies we concluded that the formal reduction potential values of imidazole nitrogen coordinated complexes decrease with the increasing number of imidazole donor atoms in the coordination sphere. However, the redox parameters of [CuHL] and [CuHL] complexes containing amide nitrogen coordination can be determined as well. All formal potential values of [CuL], [CuHL] and [CuHL] complexes fall in the middle potential range of SOD activity. Finally, after the detailed analysis of species distribution curves based upon the equilibrium data SOD activity of copper(II) containing systems at two pH (pH=6.8 and 7.4) were determined. The imidazole coordinated [CuL] complexes of the multihistidine peptide containing the HXH sequence exhibit the most significant activity, but the presence of amide nitrogen coordinated species with slightly distorted geometry could considerably contribute to the SOD activity.
提交并完成了具有末端保护的多组氨酸肽的铜（II）配合物的电化学和 SOD 活性测量的结果，这些配合物可能模拟 CuZnSOD 酶的活性部位，并完成了一些铜（II）-配体体系的溶液平衡研究。平衡数据证实，热力学稳定性随氨基酸序列中组氨酸残基数量的增加而增加，然而，组氨酸残基之间的氨基酸数量和质量可以精细调节稳定性顺序。基于循环伏安法研究，我们得出结论，配位场中咪唑氮配位配合物的形式还原电位值随配位原子中咪唑供体原子数量的增加而降低。然而，也可以确定含有酰胺氮配位的 [CuHL] 和 [CuHL] 配合物的氧化还原参数。[CuL]、[CuHL] 和 [CuHL] 配合物的所有形式电位值均落在 SOD 活性的中间电位范围内。最后，根据平衡数据的物种分布曲线的详细分析，在两个 pH 值（pH=6.8 和 7.4）下测定了含铜（II）系统的 SOD 活性。含有 HXH 序列的多组氨酸肽的咪唑配位 [CuL] 配合物表现出最显著的活性，但具有略微扭曲几何形状的酰胺氮配位物种的存在可以极大地促进 SOD 活性。
