Study on interaction between a new fluorescent probe 2-methylbenzo[b][1,10]phenanthrolin-7(12H)-one and BSA

• Published in: Analyst (London) Vol. 136; no. 5; pp. 973 - 978
• Main Authors: Qiu, Bin, Guo, Longhua, Chen, Mingluan, Lin, Zhenyu, Chen, Guonan
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 07.03.2011
• Subjects: Analytical chemistry; Binding Sites; Chemistry; Exact sciences and technology; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Fluorescent Dyes - metabolism; Hydrophobic and Hydrophilic Interactions; Limit of Detection; Phenanthrolines - chemical synthesis; Phenanthrolines - chemistry; Phenanthrolines - metabolism; Serum Albumin, Bovine - chemistry; Serum Albumin, Bovine - metabolism; Spectrometric and optical methods; Spectrometry, Fluorescence - methods; Tryptophan - chemistry; Tryptophan - metabolism; Force; Fluorescence; Molecular interaction; Binding site; Laboratory; Probe; Fluorescence spectrometry; Detection limit; Luminescence quenching; Standard curve; Ungulata; Bovine; Use; Tryptophan; Hydrophobic compound; Serum albumin; Concentration; Vertebrata; Mammalia; Fluorescent labelling; Residue; Thermodynamic parameter; Reagents; Artiodactyla; Detection
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c0an00595a

A new fluorescence reagent, 2-methylbenzo[b][1,10]phenanthrolin-7(12H)-one (mBPO), synthesized in our laboratory was used as the probe for protein and its interaction with Bovine Serum Albumin (BSA) was investigated in detail in this paper. It was found that BSA had the ability to quench the fluorescence of mBPO at 411 nm (λ(ex) = 286 nm), and the quenched intensity of fluorescence was proportional to the concentration of BSA. Based on this fact, mBPO has been used as a fluorescence probe for the detection of BSA. Under the optimal conditions, the calibration graph is linear up to 0.5 mg L(-1) for BSA and the limit of detection (LOD) was 0.06 mg L(-1). The regression equation is y = 1048.8x + 7.2093 with R(2) = 0.9913. The mechanism for the interaction of mBPO with BSA was also studied, while the binding constant and the number of binding sites were calculated. According to the thermodynamics parameter, the binding mode between mBPO and BSA was deduced. The results suggested the interaction between mBPO and BSA to be hydrophobic force in nature. It also proved that the fluorescence quenching reaction was affected by the tryptophan residue of BSA. For there are two tryptophan (Trp) residues, in site 134 and site 212 of BSA, and mBPO maybe has interaction with them respectively.