Beyond the Planck-Benzinger thermal work function: New insights into the role of molecular switches in biology

The Planck-Benzinger methodology provides a means of determining the innate temperature-invariant enthalpy, DeltaHdegrees(T-0), thermal agitation energy, or the heat capacity integrals integral(0)(T)DeltaCpdegrees(T)dT, and allows precise determination of <T-Cp>, <T-h>, <T-s>, and <T-m>. It is a method for evaluating [DeltaH(298)degrees - DeltaHdegrees(T-0)], the heat of reaction for biologic 29 molecules at room temperature, and provides for a better understanding of cooperative thermodynamic compensation. The Planck-Benzinger methodology demonstrates that macromolecular interactions will always exhibit a negative value of the Gibbs free energy change at a well-defined temperature. It can be used for determination of the thermodynamic molecular switch, where there is a change of sign in DeltaCpdegrees(T)(reaction) which determines the behavior patterns of the Gibbs free energy change. DeltaCpdegrees(+) --> DeltaCpdegrees(-) at low temperature All interacting biologic systems that we have thus far examined using the Planck-Benzinger approach point to the universality of this thermodynamic switch. (C) 2002 Wiley Periodicals, Inc.