Transition State(过渡态) A chemical reaction of substrate s to form product P goes through a transition state S*that has a higher free energy than does either S or F.(高能过渡分子) The star denotes a thermodynamic property of the transition state.The transition state is the most seldom occupied species 很难捕捉along the reaction pathway because it is the one with the highest free energy.(不稳定) .The difference in free energy between the transition state and the substrate is called the Gibbs free energy of activation or simply the activation energy,symbolized by AG*. △G*=Gs*-GsTransition State (过渡态） • A chemical reaction of substrate S to form product P goes through a transition state S* that has a higher free energy than does either S or P. （高能过渡分子） • The star * denotes a thermodynamic property of the transition state. The transition state is the most seldom occupied species 很难捕捉 along the reaction pathway because it is the one with the highest free energy. （不稳定） •The difference in free energy between the transition state and the substrate is called the Gibbs free energy of activation or simply the activation energy, symbolized by ΔG*