### ASA 125th Meeting Ottawa 1993 May

## 3pPA4. A novel acoustical approach to biomedical thermodynamics.

**Armen Sarvazyan
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Tigran Chalikian
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Kenneth J. Breslauer
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*Dept. of Chemistry, Rutgers Univ., New Brunswick, NJ 08903
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**Theodor Funck
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*Max-Planck-Inst. for Biophys. Chem., Germany
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**Vladimir Belonenko
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*VNIIGAZ, Moscow, Russia
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The principal thermodynamic quantities that describe biomolecular
structures and interactions ((Delta)G(degrees), (Delta)H(degrees),
(Delta)S(degrees), (Delta)C[sub p]) traditionally have been obtained indirectly
by measuring the temperature dependence of some equilibrium property. A more
direct approach for obtaining the relevant thermodynamic data is based on
calorimetric techniques. Significantly, these thermodynamic parameters also can
be derived by measuring the speed of sound U over a range of pressures and
temperatures, since U is a function of the second derivative of the free energy
over pressure. This talk will describe a novel approach that employs acoustical
measurements for determining energetics of biologically relevant molecules and
their interactions with small ligands (e.g., drug--biopolymer interactions).
Preliminary results will be presented that illustrate how acoustic measurements
allow for a thermodynamic characterization of model biomolecular systems.
Advantages and complementary features of the acoustical versus calorimetric
approaches for obtaining the requisite thermodynamic data will be discussed.
[sup a)]Permanent address: Inst. of Biophys., Russian Acad. Sci.