Binding Equilibrium Study Between I～-,Ni(Ⅱ),Pd(Ⅱ) And HSA Or BSA The Primary Photochemical Study Of HSA And BSA

Part IThe binding equilibrium between I ~ and human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by the resonance scattering spectrum (RSS), fluorescence spectrum and equilibrium dialysis. The enhancement of RSS were founded as the I ~ binding to the HSA and BSA, while the fluorescence quench at 350 and 700 nm. From the equilibrium dialysis results, the binding of I " to HSA and BSA fits to a phase distribution model instead of the Scatchard model, and the order of magnitude of phase distribution was found to be 104. The dialysis at different pH indicates that the binding mechanism is probably due to the electrostatic forces between the 1 " and protonated amino-acid residues.Part IIThe binding of Ni( II) ion to human serum albumin (HSA) or bovine serum albumin (BSA) has been studied by equilibrium dialysis at physiological pH(7.43) and pH(5.0). The Scatchard analysis indicates that there exists 2 strong binding sites of Ni( II) ion in both HSA and BSA at physiological pH(7.43), but only 1 strong binding site in both systems at pH(5.0). The analyses of Hill plot indicate that there exists strong positive cooperative effect in these systems. The N-terminal are probably the together strong binding locations of Ni( II) and Cu( II) ions, which suggested through competition between Ni(II) and Cu(II)> Ca(II) ions. It also suggested that N atoms are the main coordinated atoms, and Cu( II) ion induced an antagonism effect on Ni( II )-HSA and Ni(II)-BSA systems, but Ca(II) ions have litter effect on Ni(II) binding to HSA or BSA.* Project supported by the National Science Foundation of China (NO. 299621001), and the Foundation for Talents of the Ten< Hunred, Thousand in Guangxi.Part â…¢The binding of Pd(II) ions with HSA or BSA at physiological pH(7.43) is studied by the method of equilibrium dialysis. The results from Scatchard plots show that there is one strong binding site of Pd( II) ion in both HSA or BSA, it is probably located at the tripeptide segment of N-terminal sequence of HSA and BSA. The successive stability constants which are reported for the first time are obtained by non-linear least-squares method fitting Bjerrum formula. For both Pd( II )-HSA or Pd( II )-BSA systems, the order of magnitude of AT, is found to be 105. The different binding mechanism between Ni( II) - Pd( II) and I" binding to HSA and BSA is also discussed.Part â…£The Resonance Scattering Spectra (RSS) of human serum albumin (HSA) and bovine serum albumin (BSA) were reported at the first time, and were applied to study photochemical reaction of HSA or BSA. The fact of photocrosslinking self-association effect in HSA or BSA solutions is identified by the enhancement of RSS. The Fluorescence quenching at about 350 nm and 700 nm peaks proves that Tryptophan (Trp) residues are one of the photochemical activity sites in HSA or BSA molecules. The photochemical reaction mechanism of HSA or BSA is also inferred.