2020 年 30 巻 1 号 p. 4-11
Pressure is one of the fundamental parameters in thermodynamics, which can perturb physical properties of proteins as well as temperature. Here, I focused on molecular volume, partial molar volume, of proteins which depends on the hydration structure on the protein surface. Based on the thermodynamic relations, molecular volume can be estimated from the pressure, both of hydrostatic and osmotic pressure, dependence of equilibrium constants. In the protein folding of cytochrome c, the molecular volume change revealed that dehydration of hydrophobic heme group promotes the protein folding by increasing entropy. The dehydration of hydrophobic sites also facilitates the electron transfer from cytochrome c to cytochrome oxidase in the respiratory chain, which forms the “molecular breakwater” for the effective electron transfer pathway. By using pressure, we can get new insights into physical properties of proteins that can never be gained by other methodologies.
