To investigate the effect of calcium salts on the thermodn. and transport properties of aq. solns. of proteins, we report ternary diffusion coeffs. for the lysozyme-CaCl2-water ternary system at 25 C and pH 4.5. We have used our ternary diffusion coeffs. to calc. preferential-interaction coeffs. as a function of salt concn. This has allowed us to characterize protein-salt thermodn. interactions. We have obsd. the presence of large common-ion effects by examg. the dependence of the diffusion coeffs. on salt concn. Our results are compared to those previously reported for the lysozyme-MgCl2-water ternary system. We have found that the common-ion effect is essentially the same for both salt cases. On the other hand, by examg. the dependence of the preferential-interaction coeff. on salt concn., we have found that salt preferentially interacts with the protein in the lysozyme-CaCl2-water system, whereas water preferentially interacts with the protein in lysozyme-MgCl2-water system. This is consistent with the known generally larger affinity of Mg2+ for water, as compared to Ca2+, and the different roles that these two divalent metal ions play in biochem. processes. We remark that neglecting the common-ion contribution of the preferential-interaction coeff. can lead to qual. inaccurate descriptions of protein-salt aq. systems, even at high salt concns. Indeed, for the lysozyme-CaCl2 system, this approxn. would lead to interpretations inconsistent with the known destabilizing effect of calcium ions on proteins.

Multicomponent Diffusion of Lysozyme in Aqueous Calcium Chloride. The Role of Common-Ion Effects and Protein-Salt Preferential Interactions / O., Annunziata; Paduano, Luigi; J. G., Albright. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, MATERIALS, SURFACES, INTERFACES, & BIOPHYSICAL. - ISSN 1089-5647. - STAMPA. - 111:35(2007), pp. 10591-10598.

Multicomponent Diffusion of Lysozyme in Aqueous Calcium Chloride. The Role of Common-Ion Effects and Protein-Salt Preferential Interactions.

PADUANO, LUIGI;
2007

Abstract

To investigate the effect of calcium salts on the thermodn. and transport properties of aq. solns. of proteins, we report ternary diffusion coeffs. for the lysozyme-CaCl2-water ternary system at 25 C and pH 4.5. We have used our ternary diffusion coeffs. to calc. preferential-interaction coeffs. as a function of salt concn. This has allowed us to characterize protein-salt thermodn. interactions. We have obsd. the presence of large common-ion effects by examg. the dependence of the diffusion coeffs. on salt concn. Our results are compared to those previously reported for the lysozyme-MgCl2-water ternary system. We have found that the common-ion effect is essentially the same for both salt cases. On the other hand, by examg. the dependence of the preferential-interaction coeff. on salt concn., we have found that salt preferentially interacts with the protein in the lysozyme-CaCl2-water system, whereas water preferentially interacts with the protein in lysozyme-MgCl2-water system. This is consistent with the known generally larger affinity of Mg2+ for water, as compared to Ca2+, and the different roles that these two divalent metal ions play in biochem. processes. We remark that neglecting the common-ion contribution of the preferential-interaction coeff. can lead to qual. inaccurate descriptions of protein-salt aq. systems, even at high salt concns. Indeed, for the lysozyme-CaCl2 system, this approxn. would lead to interpretations inconsistent with the known destabilizing effect of calcium ions on proteins.
2007
Multicomponent Diffusion of Lysozyme in Aqueous Calcium Chloride. The Role of Common-Ion Effects and Protein-Salt Preferential Interactions / O., Annunziata; Paduano, Luigi; J. G., Albright. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, MATERIALS, SURFACES, INTERFACES, & BIOPHYSICAL. - ISSN 1089-5647. - STAMPA. - 111:35(2007), pp. 10591-10598.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/307382
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