Spectroscopic And Applied Studies On The Interactions Of Organic Compounds And Inorganic Ions With Hemoglobin

The analysis and theory study of hemoglobin are of great importance in life sciences, biochemistry and clinical physic. Hemoglobin contains tyrosine, tryptophan and phenylalanine residues which can emit fluorescence. Therefore it can be investigated using fluorescence spectroscopy. However, the intrinsic fluorescence of hemoglobin can not frequently reach the standard of sensitivity in microanalysis. While some surfactants and metal ions have strong enhancements on the fluorescence intensity of hemoglobin, which can improve the experimental sensitivity. This paper contains two sections. Firstly, the influences of various surfactants, ordinary ions, and rare earth ions on the fluorescence property of hemoglobin were investigated. And the surfactant with metal ions had strong enhancements on the fluorescence intensity of hemoglobin, so a new method of determination of hemoglobin has been established. On the other hand, the interaction mechanism about calixarenes, alkaloids and antibiotic drug with hemoglobin was studied in theory. The quenching constants, thermodynamic parameters and the distance between the acceptor and the donor were calculated, respectively. Thus, the interaction rule of protein with the compounds can be discussed under physical conditions. In addition, it can offer some information and basis for the study of life sciences.The main content of the thesis is as follows:1. The influences of surfactants and ions on the fluorescence property of hemoglobin were investigated by means of molecular spectroscopy technique. The mechanisms of fluorescence increasing, quenching and the influence on the fluorescence peaks of hemoglobin were also discussed, respectively. The surfactant hexadecyl trimethyl ammonium bromide and Zn²⁺ had strong enhancements on the fluorescence intensity of hemoglobin, so a new method of determination of hemoglobin has been established. The method has been applied to the analysis of human serum samples and the satisfactory results were obtained.2. The influences of rare earth ions on the fluorescence property of hemoglobin and deoxy-hemoglobin were investigated, respectively. The fluorescence of hemoglobin could be quenched by rare earth ions slightly. The fluorescence peaks of hemoglobin shifted upon addition of some rare earth ions. However, the rare earth ions had stronger effects on deoxy-hemoglobin than hemoglobin. The rare earth ions like Pr³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Dy³⁺ and Er³⁺ could enhance the fluorescence intensity of deoxy-hemoglobin, while La³⁺, Nd³⁺, Sm³⁺ and Y³⁺ quenched the fluorescence intensity of deoxy-hemoglobin. Meanwhile it made the fluorescence peaks of deoxy-hemoglobin red shift. The mechanisms of fluorescence increasing, quenching and its influence on the fluorescence peaks were discussed, respectively.3. The influences of 4-Sulfonic calix[4]arene, 4-Sulfonic calix[6]arene and 4-Sulfonic calix[8]arene on the fluorescence property of hemoglobin were investigated. The mechanisms and mode of interaction was also discussed. Stern-Volmer equation and UV-vis spectra indicate that the fluorescence intensity of hemoglobin was quenched by 4-Sulfonic calixarene via a dynamic quenching mechanism. And the quenching constants have been calculated. The thermodynamic parameters show that the interaction of 4-Sulfonic calixarene with hemoglobin is mainly the hydrophobic interaction. The distance r between the acceptor and the donor is determined according to Forster non-radiative energy transfer theory. The effect of 4-Sulfonic calixarene on the conformation of hemoglobin was analyzed by synchronous fluorescence spectra.4. Under physiological conditions, the influence of alkaloids (caffeine, theophylline and colchicine) and antibiotic (lomefloxacin) on the fluorescence property of hemoglobin was investigated, respectively. The quenching mechanisms of the fluorophore by the quencher were revealed. The quenching constants, the thermodynamic parameters and the distance between the acceptor and the donor were determined. The effect of the alkaloids and antibiotic on the conformation of hemoglobin was analyzed.