Molecular thermodynamic properties of protein solutions from partial specific volumes

✍ Scribed by P. E. Pjura; M. E. Paulaitis; A. M. Lenhoff

• Publisher: American Institute of Chemical Engineers
• Year: 1995
• Tongue: English
• Weight: 514 KB
• Volume: 41
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690410431

✦ Synopsis

Partial spec$c uolumes at 25°C are reported for a-chymotrypsinogen in aqueous solutions containing NaCI, citrate, and/or polyethylene glycol (PEG) ouer a range of protein concentrations. The concentration dependence of the partial specific uolume can be either positive or negatiue, depending on the soluent. For example, the partial specific uolume increases with increasing protein concentration in NaCl/citrate solutions at high salt concentrations, and decreases with increasing protein concentration in solutions containing PEG. Kirkwood-Buff solution theory has been applied to interpret these results, and it was found that the concentration dependence is determined by two factors: (1) the effective or soluent-aueruged interactions between protein molecules in solution, and (2) three-body protein -proteinsolvent and proteinsolventsolvent interactions. An approach is proposed for the experimental determination of both contributions that inuolues measuring osmotic pressures and uolumetnc properties of dilute to concentrated protein solutions.