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Ultrasonic absorption in aqueous solution of lysozyme
Author(s) -
Kanda Hiroshi,
Ookubo Norio,
Nakajima Haruhiko,
Suzuki Yasuko,
Minato Michio,
Ihara Takuro,
Wada Yasaku
Publication year - 1976
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1976.360150414
Subject(s) - chemistry , lysozyme , aqueous solution , solvent , absorption (acoustics) , molecule , titration , analytical chemistry (journal) , chromatography , organic chemistry , optics , biochemistry , physics
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.