Solvent viscosity effects on protein dynamics studied by ultrasonic absorption
Issue title: Proceedings of the Seventh International Congress of Biorheology. Part I. Palais des Congrès, Nancy, France, 18–23 June 1989. Dedicated to Richard Skalak
Guest editors: Alfred L. Copley and Jean-François Stoltz
Affiliations: Biochemistry Department, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
Note: [] Accepted by: Guest Editor S. Yedgar
Abstract: Solvent viscosity is known to play an important role in the kinetics of biochemical reactions, and has been suggested to modulate the dynamic structure of proteins. The effect of viscous cosolvents, of various molecular sizes, on the apparent ultrasonic absorption of bovine serum albumin in solution, at 37°C, has been measured in attempt to investigate the following phenomena: 1) The predicted modulating effect of viscous cosolvents on the “internal friction” of proteins, and 2) possible differences between the microscopic and macroscopic pictures of the solvent viscosity concerning the proposed effect. We have found that A) The absorption of ultrasound (3–17 MHz) by the protein increases with increasing the cosolvent concentration. B) That increase correlates with the solvent viscosity for small cosolvent molecules, but not with macromolecular cosolvents, and C) Dextran solutions with the same concentration by weight, reveal similar ultrasonic absorption, in spite of large differences in their viscosity. A possible explanation is discussed.
Keywords: viscosity, mixed solvents, proteins, ultrasonic absorption, dextran, protein dynamics
DOI: 10.3233/BIR-1990-273-439
Journal: Biorheology, vol. 27, no. 3-4, pp. 605-610, 1990
