Ultrasonic absorption in aqueous solution of lysozyme

✍ Scribed by Hiroshi Kanda; Norio Ookubo; Haruhiko Nakajima; Yasuko Suzuki; Michio Minato; Takuro Ihara; Yasaku Wada

• Publisher: Wiley (John Wiley & Sons)
• Year: 1976
• Tongue: English
• Weight: 538 KB
• Volume: 15
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1976.360150414

✦ Synopsis

Abstract

The titration curve of ultrasonic absorption at 2.82 MHz in aqueous solutions of lysozyme measured by Zana and Lang [J. Phys. Chem., 74, 2734 (1970)] is theoretically analyzed. The maxima at pH 3 and pH 11 are describable with proton‐transfer reactions of dissociable carboxyl and amino groups by assuming that volume changes due to the reactions are 2.3 and 5.2 cm^3^/mole, respectively, which are appreciably smaller than those of simple amino acids. The remaining, pH‐independent excess absorption over solvent is measured at frequencies ranging from 3 to 150 MHz. The absorption is ascribed to the internal loss of protein. The complex compressibility β′~p~ − __i__β″~p~ of lysozyme molecule is evaluated as β′~p~ = 7.2 × 10^−12^ cm^2^/dyne and β″~P~ = 4.3 × 10^−14^ cm^2^/dyne from the increments over solvent in absorption as well as in sound velocity.