Transition State Stabilization

The final piece of the puzzle in enzyme catalysis is stabilization of transition state. This refers to the ability of the enzyme to define the chemical and steric environment that are optimal for the transition state of the reaction, not just simple complementarity to the substrate
This is a modification of the original lock and key model of catalysis, where both the substrate (and in some cases the enzyme) undergo small changes in shape and chemical state upon binding
Confirmation of this effect is seen with the binding of transition state analogs, which are molecules that resemble the transition state of an enzyme-catalyzed reaction

Shown above is 2-phosphoglycolate, an analog of the transition state in the reaction catalyzed by triose phosphate isomerase. This analog binds the enzyme 100 times more strongly than either substrate