Characterizing the conformational change process of bovine serum albumin solution by fluorescence parameters / 中国药学杂志

ABSTRACT

OBJECTIVE: To study the conformational change process of bovine serum albumin (BSA) in guanidinium chloride through evaluating the fluorescence parameters, thus to elucidate the phenomenon from molecular level and to establish the relationship between the conformation of protein and the environment. METHODS: Intrinsic tryptophan fluorescence, fluorescence quenching and fluorescence probes spectrophotometry were selected to study the denaturation process of BSA in guanidinium chloride. RESULTS: An attenuation of intensity was observed both in BSA and ANS-BSA conjugates with the increasing concentration of guanidium chloride. A red shift on fluorescence emission peak occurred in the ANS-BSA conjugates, while the same result appeared in BSA only after a blue shift. The fluorescence quenching constant Ksv reduced to its minimum 3.469 × 10 L · mol-1 · s-1 in 0.5 mol · L-1 guanidium. CONCLUSION: It was shown that the denaturation process of BSA in guanidinium chloride was consistent with a three-state model, and the conformational change of the binding site on BSA of ANS was much more sensitive than that of tryptophane residue.