ABSTRACT
Objective To explore the mechanism of the interaction between sulfur dioxide(SO2) and bovine serum albumin (BSA). Methods The spectrum characteristic of the interaction between SO2 and BSA was studied by fluorescence quenching spectrum and three dimensional fluorescence spectrum. Results The binding constants and thermodynamic parameters of SO2 with BSA were calculated at different temperatures. The quenching mechanism of BSA by SO2 was determined,the result showed that it did not belong to dynamic quenching but belonged to static quenching,which produced the complex. The hydrophobic interaction and electrostatic force played a main role in the binding of SO2 with BSA and only about one binding site occurred in the reaction. There was a certain influence to the conformation of BSA after adding SO2. Conclusion The quenching reaction of BSA by SO2 was weak. SO2 dissolved in body fluid easily and then SO32-and HSO3-are generated in vivo.