Denaturation studies on bovine serum albumin–bile salt system:Bile salt stabilizes bovine serum albumin through hydrophobicity / 药物分析学报

Protein denaturation is under intensive research, since it leads to neurological disorders of severe con-sequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance, especially when proteins are used as drug molecules or vaccines. It is preferred to add pharmaceutical excipients in protein formulations to avoid denaturation and thereby stabilize them. The present study aimed at using bile salts (BSs), a group of well-known drug delivery systems, for stabilization of proteins. Bovine serum albumin (BSA) was taken as the model protein, whose association with two BSs, namely sodium cholate (NaC) and sodium deoxycholate (NaDC), was studied. Denaturation studies on the pre-formed BSA-BS systems were carried out under chemical and physical denaturation conditions. Urea was used as the chemical denaturant and BSA-BS systems were subjected to various temperature conditions to understand the thermal (physical) denaturation. With the denaturation conditions prescribed here, the data obtained is informative on the association of BSA-BS systems to be hydrophobic and this effect of hydrophobicity plays an important role in stabilizing the serum albumin in its native state under both chemical and thermal denaturation.

Role of the Trp-disulfide Triads in the UV Light Induced Degradation of a Monoclonal Antibody scFv.

Proteins are targets for photodegradation due to absorption of incident light by endogenous chromophores, e.g aromatic side chains. In this work we study the role of Trp-disulfide triads in the light induced loss of immunoglobulin activity. Study Design: We investigated a single chain variable fragment (scFv) of the Trp-disulfide triad containing monoclonal antibody 82D6A3. The scFv binds to von Willebrand factor (VWF) and upon illumination with near UV-B-light the scFv partially loses its binding capacity to VWF. In order to relate this observed degeneration to the specific Trp-disulfide triads, we mutated W35(VL) and W36(VH) which are in direct contact with the disulfide

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

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.