1. Enzymes
Section 1.4

2. Enzymes Enzymes are protein catalysts..
Enzymes; specialized globular proteins used by cells to help with metabolic reactions.

3. A catalyst is a substance that speeds up a chemical reaction without being consumed in the process.
Catalysts allow reactions to proceed at suitable rates at moderate temperature by reducing the activation energy(EA) barrier.

5. The substrate is the reactant that an enzyme acts on when it catalyzes a chemical reaction.
The location where the substrate binds to the enzyme is called the active site and is usually a depression in the three-dimensional structure of the protein.
The attachment of the substrate to the enzyme’s active site creates the enzyme-substrate complex.

6. The active site of an enzyme can lower the EA because of special functional groups of the amino acids interac with the substate causing the bonds to break.

7. Catalytic Cycle

8. Enzymes are named according to their function.
ex: fat hydrolyzing enzymes are called lipases
Temperature and pH levels affect enzyme activity.
Some enzymes require cofactors (ex: zinc ions) or coenzymes (ex:vitamin B) before they can work properly.
Inhibitors can block an enzyme’s active site or change the shape of the enzyme thus also affecting enzyme activity.

9. Homework: Questions page 77 # 1-8