In reexamining the thermodynamic parameters of a number of self-associating protein systems in the standard state near 300 K, we found that at the stable temperature [T-s], the thermodynamic quantities Delta G degrees(T-s) and Delta W degrees(T-s) reach a minimum and maximum, respectively, while T Delta S degrees(T-s) approaches zero. On the basis of the Planck-Benzinger thermal work function, Delta W degrees(T) = Delta H degrees(T-0) - Delta G degrees(T). Therefore Delta H degrees(T-0) = Delta W degrees(T-s) + Delta G degrees(T-s) at [T-s]. Values for Delta H degrees(T-0) at [T-s] for six self-associating protein systems were found to deviate by less than 0.0556 from values for Delta H degrees(T-0) at 0 K. We have demonstrated the universal applicability of the Planck-Benzinger thermal work function in the analysis of hydrophobic enhancement for protein folding, self-associating protein systems, micellization, and formation of biological membranes. Benzinger’s definition is applied in measuring Delta H(T-0) for DNA unwinding and protein unfolding in the non-standard state near 340 K. Delta H(T) = Delta W(T-0) + integral(T0)(T) Delta Cp(T) dT at the melting temperature, [T-m], where Delta H(T) and T Delta S(T) are of the same magnitude, Delta W(T) = Delta H(T-0) and Delta G(T) approaches zero. Values for Delta H(T-0) at [T-m] for the proteins we examined deviated by less than 0.04% from values for Delta W(T-0) at 0 K. The heat of reaction of any biological system consists of two terms, the heat capacity integral between product and reactant, and the temperature-invariant chemical bond energy, Delta H(T-0), which is a primary, indispensable source of the energy which allows life processes to proceed with quantitative precision. Failure to evaluate Delta H degrees(T-0) or Delta H(T-0) in assessing any biological system will thus give only a partial picture of the processes taking place within that system.