Electroviscous effect of lysozyme in aqueous solutions

✍ Scribed by Michiro Komatsubara; Kazuo Suzuki; Haruhiko Nakajima; Yasaku Wada

• Publisher: Wiley (John Wiley & Sons)
• Year: 1973
• Tongue: English
• Weight: 330 KB
• Volume: 12
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1973.360120804

✦ Synopsis

Abstract

Reduced viscosity of a dilute aqueous solution of hen egg white lysozyme is measured in the pH range from 1.4 to 12.7 for various NaCI concentrations. The viscosity decreases with increasing pH below the isoelectric point (pH 11) on account of diminution in the electroviscous effect, reaches a minimum at pH 11, and then increases at high pH's because of coagulation. The electroviscous effect is depressed by the increase in the small ion concentration. The dependence of reduced viscosity on small ion concentration and pH is discussed on the basis of Booth's theory and a partial agreement between theory and experiment is obtained. The discrepancy between theory and experiment is attributed to non‐spherical distribution of charges in the protein. The volume of lysozyme obtained through Einstein's equation by extrapolating the reduced viscosity to a sufficiently high ion concentration compares well with the molecular volume in the crystal.