2,5-di-[2-(3,5-bis(2-pyridylmethyl)amine -4-hydroxy-phenyl) ethylene] pyrazine zinc complex as fluorescent probe for labeling proteins

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2008-10, Vol.70 (5), p.1127-1133
• Main Authors: Wu, Fang-Ying, Xie, Fei-Yan, Wu, Yu-Mei, Hong, Jong-In
• Format: Article
• Language: English
• Subjects: 2,5-di-[2-(3,5-bis(2-pyridylmethyl)amine -4-hydroxy-phenyl) ethylene] pyrazine; Animals; Binding Sites; Cattle; Fluorescent Dyes - analysis; Fluorescent Dyes - chemistry; Fluorescent probe; Humans; Molecular Structure; Organometallic Compounds - analysis; Organometallic Compounds - chemistry; Serum Albumin - analysis; Serum Albumin - chemistry; Serum albumins; Spectrometry, Fluorescence; Titrimetry; Zinc complex
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2007.10.028

The binding characteristics between 2,5-di-[2-(3,5-bis(2-pyridylmethyl)amine -4-hydroxy-phenyl) ethylene] pyrazine ( 1) or its complex ( 1-Zn) and serum albumins were studied by fluorescence spectroscopy in pH 7.4 aqueous solution. 1-Zn emitted weak fluorescence at 580 nm in a pH 7.4 Tris–HCl buffer solution when excited at 435 nm, however, the fluorescence intensity increased upon addition of serum albumins with the blue shift of emission peak to 524 nm. The binding constants were estimated as 8.40 × 10 7 and 3.03 × 10 6 mol −1 L for bovine serum albumin (BSA) and human serum albumin (HSA) respectively, and the number of binding sites was 1 for each. The quenching mechanism of fluorescence of serum albumins by 1-Zn was considered as a static quenching process. The binding distance between 1-Zn and serum albumins and the energy transfer efficiency were obtained based on the theory of Förester spectroscopy energy transfer. The effect of 1-Zn on the conformation of serum albumins was further analyzed using synchronous fluorescence spectrometry. The experiment results clearly showed that 1-Zn is a highly sensitive protein sensor.