One way in which an enzyme can lower the activation energy required for a reaction is to bind the substrate(s) and distort its structure so that the substrate more closely resembles the transition state of the reaction

Question

This mechanism will be facilitated if the shape and chemical properties of the enzyme's active site are more complementary to the transition state than to the undistorted substrate; in other words, if the enzyme were to have a higher affinity for the transition state than for the substrate. Knowing this, your friend looked in an organic chemistry textbook to identify a stable chemical that closely resembles the transition state of a reaction that converts X into Y. She generated an antibody against this transition-state analog and mixed the antibody with chemical X. What do you think might happen?

Answer 1

If your friend was lucky, she made a "catalytic antibody" that catalyzed the conversion of X into Y. Such catalytic antibodies have been isolated and shown to catalyze a variety of reactions, but with lower efficiency than genuine enzymes.