In biophysics, the kinetic states of molecules play a determining role in the metabolic and physiological processes in which they take part. Now, a paper published in the journal Proceedings of the National Academy of Sciences (PNAS) specifies for the first time the levels of energy, the entropy and the enthalpy of protein folding. To do so, the team used a device with optical tweezers that enables changing the experimental temperature between 5ºC and 40ºC.