Kenneth J. Breslauer
Dept. of Chemistry, Rutgers Univ., New Brunswick, NJ 08903
Max-Planck-Inst. for Biophys. Chem., Germany
VNIIGAZ, Moscow, Russia
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.