The interaction between silicotungstic heteropolyacid and bovine hemoglobin (BHb) was investigated using fluorescence and UV-Vis. The experimental results show that the fluorescence quenching of BHb by silicotungstic ...The interaction between silicotungstic heteropolyacid and bovine hemoglobin (BHb) was investigated using fluorescence and UV-Vis. The experimental results show that the fluorescence quenching of BHb by silicotungstic heteropolyacid is a result of the formation of SiW-BHb complex; and the quenching mechanism is mainly static quenching. The binding site number n, apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The process of binding SiW molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Electrostatic interaction plays a major role in stabilizing the complex. The effect of silicotungstic heteropolyacid on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy.展开更多
The interaction of Methylthymol Blue(MTB)-Zinc! compound and Alizarin Red S(ARS)-Aluminum" compound with Bovine serum albumin (BSA) was investigated by UV-Vis spectrophotometric method in acidic buffer solution. ...The interaction of Methylthymol Blue(MTB)-Zinc! compound and Alizarin Red S(ARS)-Aluminum" compound with Bovine serum albumin (BSA) was investigated by UV-Vis spectrophotometric method in acidic buffer solution. MTB-Zn!-BSA was a blue color compound, which possesses maximum absorption at 613 nm with 172 nm, 174 nm and 18 nm of red shift compared to the MTB, MTB-BSA and MTB-Zn! complexes respectively. Dual wavelength substantial amount ratio method, balance dialysis substantial amount ratio method and unity wavelength substantial amount ratio method were compared. The following results were obtained: the apparent molar absorptivity of MTB-Zn! with BSA was ε=2.20×104 L·mol-1·cm-1. Conditional proportion were defined, nMTB∶nZn!∶nBSA=2∶2∶1; condition combination constant, K=2.07×1010. Combination proportion were defined, nARS∶nAl"∶ nBSA=6∶4∶1. Condition equilibrium constant of reaction of ARS-Al" with BSA was K=8.80×108. The apparent mo- lar absorptivity of ε=2.65×104 L·mol-·1cm-1. It is suggested that combination between BSA and MTB-Zn" is due to coordination force. That combination between BSA and ARS-Al" is due to the coordination bond and electro- static force.展开更多
Chinese liquor Moutai is the “National alcoholic drink” in China and plays a very important role of social activities in Chinese people’s life. In pursuit of high profits, some illegal counterfeit Moutai liquors ha...Chinese liquor Moutai is the “National alcoholic drink” in China and plays a very important role of social activities in Chinese people’s life. In pursuit of high profits, some illegal counterfeit Moutai liquors have begun to appear in the market. Therefore, it is an urgent need for new techniques to discriminate the genuine and counterfeit Moutai liquor. In this work, the conventional Ultraviolet-Visible (UV-Vis) spectroscopy and two-dimensional correlation UV-Vis spectroscopy are applied to obtain the UV-Vis characteristic of Moutai liquor and counterfeit one, respectively. The experimental results reveal that the conventional UV-Vis spectra of the genuine and counterfeit Moutai liquor are similar. However, the two-dimensional correlation UV-Vis spectra of them are different and this method would be applied to differentiate the counterfeit Moutai liquor from the genuine Moutai liquor. Compared with conventional methods, this novel method has the advantages of easy operation, simple instrumentation and direct recognition, which make it a potential tool in the fields of food safety.展开更多
文摘The interaction between silicotungstic heteropolyacid and bovine hemoglobin (BHb) was investigated using fluorescence and UV-Vis. The experimental results show that the fluorescence quenching of BHb by silicotungstic heteropolyacid is a result of the formation of SiW-BHb complex; and the quenching mechanism is mainly static quenching. The binding site number n, apparent binding constant KA and corresponding thermodynamic parameters were measured at different temperatures. The process of binding SiW molecule on BHb was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Electrostatic interaction plays a major role in stabilizing the complex. The effect of silicotungstic heteropolyacid on the conformation of BHb was analyzed using synchronous fluorescence spectroscopy.
文摘The interaction of Methylthymol Blue(MTB)-Zinc! compound and Alizarin Red S(ARS)-Aluminum" compound with Bovine serum albumin (BSA) was investigated by UV-Vis spectrophotometric method in acidic buffer solution. MTB-Zn!-BSA was a blue color compound, which possesses maximum absorption at 613 nm with 172 nm, 174 nm and 18 nm of red shift compared to the MTB, MTB-BSA and MTB-Zn! complexes respectively. Dual wavelength substantial amount ratio method, balance dialysis substantial amount ratio method and unity wavelength substantial amount ratio method were compared. The following results were obtained: the apparent molar absorptivity of MTB-Zn! with BSA was ε=2.20×104 L·mol-1·cm-1. Conditional proportion were defined, nMTB∶nZn!∶nBSA=2∶2∶1; condition combination constant, K=2.07×1010. Combination proportion were defined, nARS∶nAl"∶ nBSA=6∶4∶1. Condition equilibrium constant of reaction of ARS-Al" with BSA was K=8.80×108. The apparent mo- lar absorptivity of ε=2.65×104 L·mol-·1cm-1. It is suggested that combination between BSA and MTB-Zn" is due to coordination force. That combination between BSA and ARS-Al" is due to the coordination bond and electro- static force.
文摘Chinese liquor Moutai is the “National alcoholic drink” in China and plays a very important role of social activities in Chinese people’s life. In pursuit of high profits, some illegal counterfeit Moutai liquors have begun to appear in the market. Therefore, it is an urgent need for new techniques to discriminate the genuine and counterfeit Moutai liquor. In this work, the conventional Ultraviolet-Visible (UV-Vis) spectroscopy and two-dimensional correlation UV-Vis spectroscopy are applied to obtain the UV-Vis characteristic of Moutai liquor and counterfeit one, respectively. The experimental results reveal that the conventional UV-Vis spectra of the genuine and counterfeit Moutai liquor are similar. However, the two-dimensional correlation UV-Vis spectra of them are different and this method would be applied to differentiate the counterfeit Moutai liquor from the genuine Moutai liquor. Compared with conventional methods, this novel method has the advantages of easy operation, simple instrumentation and direct recognition, which make it a potential tool in the fields of food safety.
