Study on the binding of Arsenazo-TB to human serum albumin by Rayleigh light scattering technique and FT-IR.
The interaction between Arsenazo-TB and human serum albumin (HSA) was studied by Rayleigh light scattering (RLS) technique and Fourier transformed IR (FT-IR). The binding parameters of Arsenazo-TB with HSA were studied at different temperature of 288, 298, 308, 318 K under the optimum conditions. It is indicated by the Scatchard plots that the binding constant K decreased from 5.03 x 10(7) to 7.13 x 10(6) and the maximum binding number N reduced from 53 to 36 with the increasing of the temperature. The binding process was exothermic, enthalpy driven and spontaneous, as indicated by the thermodynamic analyses, and the major part of the binding energy is hydrophobic interaction. The free energy change deltaG0, the enthalpy change deltaH0 and the entropy change deltaS0 of 288 K were calculated to be -42.46 kJ/mol, -49.17 kJ/mol and 318.15 J/mol K, respectively. The alterations of protein secondary structure in the presence of Arsenazo-TB in aqueous solution were quantitatively calculated from FT-IR spectroscopy with reductions of alpha-helix from 57% to 40% and with increases of beta-sheet from 36% to 39%, beta-turn from 7% to 21%.
Dong
Lijun
L
Department of Chemistry, Lanzhou University, Lanzhou 730000, China.
Chen
Xingguo
X
Hu
Zhide
Z
D001150:Arsenazo III / Q000031:analogs & derivatives* / Q000737:chemistry; D006801:Humans; D008027:Light; D009281:Naphthalenes / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D012709:Serum Albumin / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
C509576:Arsenazo-TB; D009281:Naphthalenes; D012709:Serum Albumin; D001150:Arsenazo III