Ratchet model of motor proteins and its energetics

Abstract

We describe the energetics of motor proteins by taking F1 -ATPase as an example. To clarify the meaning of the mechanical works which are experimentally measured, we first identify the heat, which satisfies the second law of thermodynamics, and next formulate the work through the first law of thermodynamics. The theoretical expressions of the mechanical works reveal that the experimentally measured works have a theoretical basis. Contrary to the mechanical work, the measurement of the heat is still developing. We introduce an attempt to measure a part of the heat, which is related to the experimentally accessible quantities through a nonequilibrium equality.