Bovine serum albumin

About: Bovine serum albumin is a research topic. Over the lifetime, 19981 publications have been published within this topic receiving 571291 citations. The topic is also known as: BSA.

Spectroscopic investigation of the interaction between rifabutin and bovine serum albumin

Abstract: The binding of rifabutin (RB) to bovine serum albumin (BSA) was investigated by fluorescence spectroscopy and circular dichroism (CD). RB effectively quenched the intrinsic fluorescence of BSA via a combination of static and dynamic quenching. The thermodynamic parameters, Δ H ° and Δ S ° were estimated to be −5.14 kJ mol −1 , +120.44 J mol −1 K −1 according to the van’t Hoff equation. This indicates that hydrophobic interaction plays a major role in stabilizing the RB–BSA complex. The high order of magnitude of k q (10 15 ) for RB–BSA suggests that the process of energy transfer occurs through intermolecular interaction. Binding studies in the presence of fluorescence probe, 8-anilino-1-naphthalein-sulphonic acid (ANS), showed that RB competed with ANS for hydrophobic sites on the surface of BSA. The effect of metal ion on the binding constant of RB–BSA complex varied with metal ion. Cu 2+ and Ca 2+ increased the binding constant, whereas Zn 2+ and Mg 2+ decreased the binding efficacy of RB to BSA. Synchronous fluorescence spectra and CD data revealed that RB induced the conformational change of BSA.

pK change of imidazole groups in bovine serum albumin due to the conformational change at neutral pH.

Abstract: a b s t r a c t : The pH-dependent change in conformation o f bovine serum albumin, located between pH 6 and 9 (neutral transition), was studied by means o f optical rotation measurements at 313 nm and hydrogen ion titration experiments, both in the presence o f KC1 or CaClj. The optical rotatory dispersion measurements revealed that with CaCl2 the transition proceeds at lower pH values and within a smaller pH range than without calcium. From an analysis o f the titration curves, combined with the observed influence o f calcium ions on the neutral transition, it could be concluded that the transition causes a p K shift o f certain groups, probably imidazole groups, since as a consequence o f the pK shift protons are released in the neutral region. That these groups are indeed imidazole groups was further confirmed by measuring the apparent heat o f proton dissociation. The highest pK was found in the low pH conformation. This suggests that in this conformation several histidyl residues are involved in salt bridges. The effect o f calcium on the neutral transition indicates that the affinity o f albumin for protons decreases upon calcium binding. The relation between calcium and proton binding to albumin shows much resemblance with the Bohr effect o f hemoglobin, i.e., the relation between oxygen and proton binding.