Question

How does an enzyme lower the activation energy? What are the specific catalytic mechanisms? What are the three types of specific catalytic mechanisms?

Answer 1

a) It reduces the amount of energy by hold the substrates in such a way as to distort the substrate bonds closer to their form in the transition state.  

b) It decreases the activation energy by create a charge distribution opposite to that of the transition state. It case the lowering of the transition state.

c) It may reduce the reaction entropy ΔS^‡ by bringing substrates together in the correct orientation to react.

d) It will form new bonds in the complexs that would be difficult to form without the enzyme.It give a completely different chemical pathway for the reaction.

Specific catalytic mechanisms

1. Electrostatic catalysis

Stabilization of charged transition states by residues in the active site forming ionic bonds with the intermediate.

2. Covalent catalysis

Covalent catalysis involves the substrate forming a transient covalent bond with residues in the enzyme active site or with a cofactor.

3. Metal ion catalysis

The presence of a metal ion in the active site participates in catalysis by coordinating charge stabilization and shielding