Research On Binding Of Acid Yellow G And Tartrazine To Serum Albumins And Other Related Issues

The rapid development of society has not only improved the living standard of humans, but also poses great threat to the human health. In recent years, considerable attention has been paid to the globally environmental pollution. However, humans are still exposed to these persistent pollutants via air, water, foods and other ways, which would transport directly through the digestive tract, respiratory tract and skin contact channels into the biological body and produce the toxicity to humans by the direct or indirect interactions with biological macromolecules in vivo, such as proteins, nucleic acids, and enzymes. Therefore, it is of great importance to research on the potential toxicity of pollutants to the bimolecular, which will help more to complement studies on the environmental risk assessment of pollution, and provide some reference and technical support for the relevant standard of protecting human health and safety.There are lots of toxicity evaluations for pollutants, of which the most commonly two are animal experiments and epidemiological investigations, but these methods can not explain the toxicity mechanism from the molecular level. In order to compensate for this, we adopted the spectroscopic techniques to study the toxicity mechanism in vitro from the protein level, which will help to understand and predict the toxicity of the contaminants to the protein in the blood, and it also provide a new perspective to clarify the toxicity of contaminants.In this paper, the mechanism interactions of two common soluble azo dyes to serum albumins have been investigated under simulated physiolocigal condition by means of fluorescence, synchronous fluorescence, three-dimensional fluorescence, UV-vis absorption (UV), and circular dichroism (CD). We also designed a device to verify the inner filter effect by experiment and clarified the related issues about the spectral characteristics of proteins from a new perspective.The paper is divided into six parts, of which the main experiments consist of four parts:Part 1:We studied the effect of acid yellow (AY 11) exposure to the common protein bovine serum albumin (BSA) by several spectroscopic techniques including fluorescence, UV and CD. It was found that AY could interact with BSA moderately by competing with the endogenous and exogenous compounds to the protein binding, and it caused conformational changes of protein, which could affect its activity or even change its physiological function. Besides, AY was proved to have little impact on the fluorescence of BSA by a verification experiment.Part 2:We selected two serum albumins (SA), human serum albumin (HSA) and BSA, as the targets to evaluate the toxic effects of tartrazine (AY23) by means of the above techniques and a more intuitive three-dimensional fluorescence spectroscopy from the protein level. And the results confirmed that AY23 indeed impact the conformation of both HSA and BSA.A series of problems in the protein study were founded from these above parts, such as the inner filter effect to the fluorescence, and the unclearly explanation or deviation on the protein spectral characteristics. Therefore, these problems were studied in the next two sections.Part 3:With their own colors, the dyes will cause the light absorption among the specific wavelengths, which may possible interfere with the protein fluorescence spectra. To determine the impact of dyes absorption, a series of experiments were made and the results proved that there was little effect on the fluorescence spectra because of the absorption. However, in other systems, the absorption has serious effects on the results of the protein fluorescence. Thus we designed a device to eliminate the impact of absorption, and the relevant results have been patented.Part 4:The adoption of three-dimensional fluorescence spectroscopy in the second part revealed that some protein spectral characteristics were not explained perfectly and some deviations were founded in the explanation. As a result, in this section, we simulated the protein with the twenty amino acids to obtain the specific protein spectra by means of the three-dimensional fluorescence spectroscopy and UV methods. The improvement of the protein spectra explanation will provide a detailed reference to the future molecular study.