Faculty of Science, Laboratory of Physical Chemistry, Department of Chemistry, University of Guilan, Rasht, Iran.
Anal Cell Pathol (Amst). 2013;36(1-2):21-6. doi: 10.3233/ACP-130074.
The interaction of a water-soluble cationic porphyrin, Cobalt(III) 5, 10, 15, 20-tetrakis (1-methylpyridinium-4-yl) porphyrin [Co(III)TMPyP], with bovine serum albumin (BSA) has been studied in 1 mM phosphate buffer pH 7.0 containing 5 mM NaCl by UV-vis absorption, resonance light scattering (RLS) and fluorescence spectroscopies at 25°C. The results of RLS studies represent no aggregate formation of porphyrin in the surface of BSA and low tendency of this porphyrin for aggregate formation. The binding of porphyrin complex to BSA quenches fluorescence emission of BSA via a dynamic mechanism and the quenching process obeys a linear Stern-Volmer relationship. The values of Stern-Volmer constants, KSV, was determined nearly 10(5) M(-1), that depend on BSA concentration. The average aggregation number of BSA calculated from the analysis of fluorescence quenching data indicates that absence of any porphyrin induced aggregation of BSA due to its interaction with porphyrin complex. The binding of Co(III) TMPyP had no obvious effect on the molecular conformation of the protein. Electrostatic force played an important role in the binding due to the opposite charges on porphyrin and the protein.
在 1 mM 磷酸盐缓冲液 pH 7.0 中，含有 5 mM NaCl，通过紫外可见吸收、共振光散射（RLS）和荧光光谱法，在 25°C 下研究了水溶性阳离子卟啉钴（III）5、10、15、20-四（1-甲基吡啶-4-基）卟啉 [Co（III）TMPyP] 与牛血清白蛋白（BSA）的相互作用。RLS 研究的结果表明，在 BSA 的表面没有卟啉形成聚集体，并且该卟啉形成聚集体的趋势较低。卟啉配合物与 BSA 的结合通过动态机制猝灭 BSA 的荧光发射，猝灭过程遵循线性 Stern-Volmer 关系。Stern-Volmer 常数 KSV 的值接近 10(5) M(-1)，取决于 BSA 浓度。从荧光猝灭数据分析得出的 BSA 的平均聚集数表明，由于其与卟啉配合物的相互作用，不存在任何卟啉诱导的 BSA 聚集。Co（III）TMPyP 的结合对蛋白质的分子构象没有明显影响。由于卟啉和蛋白质带相反电荷，静电力在结合中起着重要作用。
