1. How enzyme function

2. Chemical reaction The cells carries out many chemical reactions.
A + B C +D
reactants products
All the reactions that occur in a cell have an enzyme.

3. Enzymatic action
Enzymes are organic catalysts that speed metabolic reactions.
Most of the enzymes are proteins.
The reactants in an enzymatic chemical reaction are called substrates.
E + S ES E + P

4. Enzymes can be used over and over again.
Enzymes have specific shape accommodating the shapes of their substrate.
Enzymes can be used over and over again.
Active site

5. Catalase
Catalase speeds the breakdown of hydrogen peroxide to water and oxygen
2H2O H2O + O2
catalase

6. Factors affecting enzyme activity
Temperature
Concentration (of enzyme or substrate) pH

7. Temperature Cold (ice bath)— slow chemical reaction
Warm— speed chemical reaction
Hot (boiling water bath)— enzyme denature

8. Concentration (of enzyme or substrate)
Low—slower chemical reaction
High— faster chemical reaction

9. pH pH<7 acidic pH=7 neutral pH>7 alkline
Each enzyme— optimum pH speed the reaction best
Low / high—affects hydrogen bonding and the structure of enzyme, reduced activity

10. Summary Factors Promote Enzyme Activity Inhibit Enzyme Activity
Temperature
Concentration pH

11. Experiments
1. Catalase Activity: what does the height of the bubble column mean? what’s the function of catalase? page 59
2. Effect of Temperature: finish table 5.2 page 60
3. Effect of Enzyme Concentration: finish table page 61
4. Effect of pH on Enzyme Activity: finish table 5.4 page 62 11