How Enzyme Catalysis Is Achieved

Front 1

Proximity and Orientation

Back 1

If the reactants and chemical R groups are aligned properly with the active site, the reaction will proceed faster. Entropy loss will also be reduced because of the reduction of random tumbling and substrate stretching.

Front 2

Covalent Catalysis

Back 2

The transient covalent bond of the substrate with an amino R group in the active site can reduce the energy of the later transition states. The serine hydroxyl group can form the relatively stable acyl-enzyme intermediate in proteases like chymotrypsin. the SH group is always in the right place, so it again speeds up the reaction.

Front 3

Acid-base catalysis

Back 3

Enzyme provides acid-base catalysis because it can act as either a proton donor or acceptor. The histidine imidazole group is usually involved because it can be either an acid or a base at neutral pH.

Front 4

Electrostatic Destabilization

Back 4

Enzyme provides electrostatic destabilization because of the repulsive charges between enzyme and substrate. When these are relieved, the reaction occurs more rapidly.

Front 5

Transition state bonds

Back 5

Tightest binding of the enzyme is with the transition state which lowers activation energy and speeds up the reaction.