What Are Enzymes?Proteins, with complex 3-d shapes

Have an active site which can bind a substrate (reactants)

Help Chemical Reactions Occur

Notice the enzyme is not used up in the reaction!

Only a certain substrate will fit in the active site

How?Allows bonds in substrate to be

broken more easily, with less input of energy

Another Example

Reaction Energy Diagrams

Activation Energy

Activation EnergyInput of energy required to break

initial bonds and begin the reactionEven if reaction will release energy

Enzymes Lower EaMake the transition state easier to

reach

Endergonic vs. Exergonic

Specificity of Active Sites

Enzymes only catalyze substrates with a complementary shape

Any changes to the shape of the enzyme will disable the activity of the active site