Kocyła Anna, Pomorski Adam, Krężel Artur
Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland.
Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland.
J Inorg Biochem. 2017 Nov;176:53-65. doi: 10.1016/j.jinorgbio.2017.08.006. Epub 2017 Aug 24.
Zincon (ZI) is one of the most common chromophoric chelating probes for the determination of Zn and Cu ions. It is also known to bind other metal ions. However, literature data on its binding properties and molar absorption coefficients are rather poor, varying among publications or determined only in certain conditions. There are no systematic studies on Zn and Cu affinities towards ZI performed under various conditions. However, this widely commercially available and inexpensive agent is frequently the first choice probe for the measurement of metal binding and release as well as determination of affinity constants of other ligands/macromolecules of interest. Here, we establish the spectral properties and the stability of ZI and its complexes with Zn, Cu, Cd, Hg, Co, Ni and Pb at multiple pH values from 6 to 9.9. The obtained results show that in water solution the MZI complex is predominant, but in the case of Co and Ni, M(ZI) complexes are also formed. The molar absorption coefficient at 618 nm for ZnZI and 599nm for CuZI complexes at pH7.4 in buffered (I=0.1M) water solutions are 24,200 and 26,100Mcm, respectively. Dissociation constants of those complexes are 2.09×10 and 4.68×10M. We also characterized the metal-assisted Zincon decomposition. Our results provide new and reassessed optical and stability data that are applicable to a wide range of chemical and bioinorganic applications including metal ion detection, and quantification and affinity studies of ligands of interest.
Accurate values of molar absorption coefficients of Zincon complex with Zn, Cd, Hg, Co, Ni, Cu, and Pb for rapid metal ion quantification are provided. Zincon stability constants with Zn and Cu in a wide pH range were determined.
锌试剂（ZI）是测定锌离子和铜离子最常用的发色螯合探针之一。已知它也能与其他金属离子结合。然而，关于其结合特性和摩尔吸收系数的文献数据相当匮乏，不同出版物的数据各不相同，或者仅在特定条件下测定。目前还没有在各种条件下对锌和铜与锌试剂的亲和力进行系统研究。然而，这种广泛商业化且价格低廉的试剂经常是用于测量金属结合与释放以及测定其他感兴趣配体/大分子亲和力常数的首选探针。在此，我们确定了锌试剂及其与锌、铜、镉、汞、钴、镍和铅形成的配合物在pH值从6到9.9范围内的光谱特性和稳定性。所得结果表明，在水溶液中MZI配合物占主导，但对于钴和镍，也会形成M(ZI)配合物。在pH7.4的缓冲（I = 0.1M）水溶液中，ZnZI配合物在618nm处的摩尔吸收系数和CuZI配合物在599nm处的摩尔吸收系数分别为24200和26100M⁻¹cm⁻¹。这些配合物的解离常数分别为2.09×10⁻⁹和4.68×10⁻⁹M。我们还对金属辅助的锌试剂分解进行了表征。我们的结果提供了新的且经过重新评估的光学和稳定性数据，适用于广泛的化学和生物无机应用，包括金属离子检测以及对感兴趣配体的定量和亲和力研究。
提供了锌试剂与锌、镉、汞、钴、镍、铜和铅形成的配合物用于快速金属离子定量的准确摩尔吸收系数值。测定了锌试剂在宽pH范围内与锌和铜的稳定常数。
