Lifetimes are much longer than transition states. The Born-Oppenheimer potential energy surface describes the potential energy of a reaction complex as a function of the positions of the atoms taking part in the reaction. The saddle point corresponds to the transition state. Maxima are points of high potential energy, from repulsion between atoms. Minima are points of low potential energy.
Enzymes hold reactants together in an optimal alignment for reaction.
Substrate binding is not necessarily inhibitory to catalysis because there can actually be an increase in entropy from the displacement of bound water molecules. Energy contributions in maintaining protein structure. A decrease in entropy in going from many possible random coils to a single protein structure. This is unfavorable to stability. A catalyst speeds up a reaction in the forward and reverse direction without being changed in the overall process.