Study On The Interaction Between Vitamin B And Protein

Protein, with very complex three dimensional space structure, is one kind of bioactive protein molecules that can realize the function of the organism in many important life and physiological phenomena, in another words, proteins involved in all life phenomena, and its structure is divided into four levels including primary, secondary, tertiary and quaternary structure. Currently the investigations between protein molecules and small molecules such as establish the combination of drugs and proteins in vitro model of physiological conditions are well studied, which can help people more deeply understanding of the interation mechanism and the rule of the effect in the molecular level through combining sites, binding constants and close degree, etc. The interactions between drugs and proteins, are very important for the understanding of protein structure and function, then for the further research of life science provides effective information and data, and have very important significance for our understanding of the distribution and transportation of drug in the body, the design of new drug, the toxicity of drug and pharmacokinetics, etc.1. The interaction between vitamin B2and trypsin was studied by using spectrophotometric techniques such as fluorescence and UV-Vis absorption in physiological buffer solutions(pH7.9). The experimental results showed that the fluorescence intensity of trypsin was strongly quenched by the addition of VB2. Spectrophotometric observations are rationalized in the terms of a static quenching process at lower concentration of VB2and a combined quenching(both dynamic and static) process at higher concentration of VB2. The binding constant K for the VB2-trypsin system were calculated and the binding distance r of1.11nm and the energy transfer efficiency (E=0.79) was obtained from the Forster non-radioactive resonance energy transfer theory. The thermodynamic parameters ofΔG is a negative value, which revealed that the binding is a spontaneous process. Negative values for both enthalpy change (ΔH) and entropy change (ΔS), indicate the binding power between VB2and trypsin is mainly hydrogen bond and van derWaals force. The interactions of the VB1-trypsin system and the VBg-trypsin system were studied by the same method, and the energy transfer distance of the two systems are determined.2. The interaction between vitamin B1and bovine hemoglobin(BHb) was studied by using spectrophotometric techniques. The fluorescence spectra showed that the fluorescence intensity of BHb was strongly quenched by the addition of VB1.The thermodynamic parameters indicated the binding power between VB1and BHb is mainly electrostatic force and the binding constants of VB1and BHb reach104magnitude, indicating that the combination of the two is stronger. The binding locality was an area0.47nm away from tryptophan residue in BHb based on the Forster non-radioactive resonance energy transfer theory, which was less than8nm so the non-radiation energy transfer was observed. The interactions of the VB2-BHb system and the VB9-BHb system were studied by the same method, and the energy transfer distance of the two systems are determined.3. The interaction of VBi-pepsin system, VB2-pepsin system and the VB9-pepsin system were studied by fluorescence spectroscopy and UV-Vis absorption. The results showed that the fluorescence of pepsin is quenched regularly by the three vitamin and The thermodynamic parameters and binding constants of the three systems are obtained at different temperatures. Synchronous spectrum was used to investigate the conformational change of pepsin with the addition of the three vitamins, respectively.