Interaction Of Three Classes Of Tetrapyrrole Compounds And Bovine Serum Albumin By Spectroscopic Methodology

The interaction between three classes of tetrapyrrole compounds and bovine serum albumin(BSA) was invesgated by spectroscopy under imitated physiological conditions. It includes the three main following parts:1. The spectroscopic techniques were used to study the interaction between 21-(Ph-N=N)-NCTPP and BSA. The results indicated that 21-(Ph-N=N)-NCTPP can quench the intrinsic fluorescence of BSA strongly via a combined(dynamic and static quenching) procedure. The binding constants and the binding sites were calculated. The thermodynamic parameters calculated at three different indicated that the binding process was spontaneous and the hydrophobic interaction played a major role in [21-(Ph-N=N)-NCTPP]-BSA binding process. Based on the F?rster non-radiation energy transfer theory, the energy transfer distance from the donor(BSA) to the acceptor(21-(Ph-N=N)-NCTPP) was estimated. What's more, the synchronous fluorescence spectra indicated that the 21-(Ph-N=N)-NCTPP has not effected the comformation of BSA.2. The interaction between Nickel(II) complexes of 5,15-diaza-10,20-dimesitylporphyrins(Ni-DAP) and bovine serum albumin(BSA) was studied at three different temperatures(298, 304 and 310 K). The values of the binding constants(Ka) were as obtained is of the order of 103, which suggested the binding process were strong. The binding sites(n) were approximately to 1, which indicated that [(Ni-DAP)-BSA] complex was formed with the molar ratio of 1:1. The thermodynamic parameters and the acting force were obtained. The binding distance between Ni-DAP and BSA were less than 7 nm, which indicated that the energy transfer from BSA to complexes occurred with high probability. Synchronous fluorescence spectroscopy confirmed that the conformation of BSA was changed by Ni-DAP because of the effect of hydrophobic enhancement.3. The fluorescence and ultraviolet spectroscopy were explored to invesgated the interation between Norcorrole and BSA. It was found that Norcorrole has a powerful ability to bind with BSA. After analyzing the fluorescence dates basd on the Stern-Volmer equation, the quenching mechanism were obtained. The quenching procedure was static at low Norcorrole concentration and a combined procedure when the Norcorrole concentration was higher. The fluorescence lifetime measurements further confirmed that the quenching mechanism was a combined quench process. According to the improved double logarithm equation, the Ka and n were calculated. Based on the Van't Hoff equation, the thermodynamic parameters(?H, ?S and ?G) and the acting force between Norcorrole and BSA were obtained. The binding distance from Norcorrole to BSA was calculated to be 3.67 nm.This paper provided some useful dates of clinicine medicine and drug transport in vivo through the investigation of the interation between three classes of tetrapyrrole compounds and BSA.