title: Ultrasonic absorption of bovine serum albumin solutions in the frequency range 60 to 160 kHz.
abstract: The ultrasonic absorption of the globular protein bovine serum albumin in aqueous solution has been measured in the frequency range 60 to 160 kHz using a 2-1 spherical resonator. The effect of pH change and of the denaturants urea, guanidine hydrochloride, and sodium dodecyl sulfate on the absorption loss has been studied. It is concluded that a significant ultrasonic absorption process exists which is related to structural helix-coil transition equilibria. For native protein the maximum loss appears to occur at a frequency at least as low as 70 kHz for a pH of about 4.2. This loss process is distinct from those arising from proton-transfer equilibria perturbations which are manifest at pH 3.2 and 11.6 and at peak frequencies of 400 kHz and above.
mesh_terms: D000818:Animals; D002417:Cattle; D019791:Guanidine; D006146:Guanidines / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012709:Serum Albumin / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000378:metabolism; D014465:Ultrasonics; D014508:Urea / Q000378:metabolism
chemical_list: D006146:Guanidines; D012709:Serum Albumin; D012967:Sodium Dodecyl Sulfate; D014508:Urea; D019791:Guanidine