Study of Interactions of Bovine Serum Albumin in Aqueous (NH₄)₂SO₄ Solution at 25 °C by Osmotic Pressure Measurements

Abstract

We have made some improvements to the osmometer described previously (Colloid Interface Sci. 1981, 79, 548-566). Using the improved osmometer, we measured the osmotic pressures of aqueous bovine serum albumin (BSA) solutions at four pH values (4.5, 4.8, 5.4, and 7.4) and at four ammonium sulfate concentrations [(0.15, 0.50, 1.00, and 1.50) mol • L -1 ]. The osmotic second virial coefficients of BSA were calculated from the osmotic-pressure data. According to the molecular thermodynamic model (Fluid Phase Equilib. 2000, 168, 229-239), the electrostatic repulsion potential, attractive dispersion potential, and ion-excluded-volume potential have been calculated. The dependence of the three potentials on solution pH and on ionic strength is discussed.

Interactions in protein mixtures. Part I: Second virial coefficients from osmometry

“…The second virial coefficient B 0 has been directly linked to the crystallization behavior of single and purified protein solutions, which was found to solely occur within a narrow range called 'crystallization slot' (Ahamed, Ottens, van Dedem, & van der Wielen, 2005;Bonnet e, Finet, & Tardieu, 1999;Ducruix, Guilloteau, Ri es-Kautta, & Tardieu, 1996;Guo et al, 1999;Mehta, White, & Litster, 2012;Wanka & Peukert, 2011;Wilson, 2003). Here most experimental data are available for BSA and lysozyme at conditions typically needed to crystallize them (Bonnet e et al, 1999;Guo et al, 1999;Kulkarni, Chatterjee, Schweizer, & Zukoski, 2000;Le Brun, Friess, Schultz-Fademrecht, Muehlau, & Garidel, 2009;Lu, Chen, Wang, & Yan, 2009;Mehta et al, 2012;Moon, Curtis, Anderson, Blanch & Prausnitz, 2000;Park & Choi, 2009;Vilker, Colton, & Smith, 1981;Wanka & Peukert, 2011). However, in areas other than protein crystallization, experimental data on second virial coefficients are rare.…”

Thermodynamics of protein aqueous solutions: From the structure factor to the osmotic pressure

“…For instance, the experimental data by Wu and Prausnitz suggests a value of B = −1.7 × 10 −4 cm 3 mol g −2 for BSA in aqueous solution with 1.0 mol L −1 sodium chloride at pH = 4.5. For BSA in aqueous solution with 1.0 mol L −1 ammonium sulfate at pH = 4.8, a value of B = −0.77 × 10 −4 cm 3 mol g −2 was reported …”

Binding of glutathione and melatonin to pepsin occurs via different binding mechanisms

“…Equilibrium microdialysis was performed with the apparatus that reported by our group before (Lu et al 2009;Li and Yang 2015). It consists of two chambers separated by membrane (MWCO 10,000) impermeable to particles larger than 10,000 Da.…”