Enthalpy-entropy compensation and the isokinetic temperature in enzyme catalysis
Enthalpy-entropy compensation supposes that differences in activation enthalpy delta-H-++ for different reactions (or, typically inbiochemistry, the same reaction catalysed by enzymes obtained from different species) may be compensated for bydifferences in activation entropy delta-S-++. At the isokinetic temperature the compensation is exact, so that all samples have thesame activity. These ideas have been controversial for several decades, but examples are still frequently reported asevidence of a real phenomenon, nearly all of the reports ignoring or discounting the possibility of a statistical artefact. Evenfor measurements in pure chemistry artefacts occur often, and they are almost inescapable in enzyme kinetics and otherfields that involve biological macromolecules, on account of limited stability and the fact that kinetic equations are normallyvalid only over a restricted range of temperature. Here I review the current status and correct an error in a recent bookchapter.