1. Enzymes

2. Enzymes are… Proteins that act as catalysts (accelerate reactions) by creating a new reaction pathway Are specific for what they catalyze and do not permanently change during reactions End in the word -ase

3. Function of Enzymes Enzymes work by lowering the activation energy (the amount of energy needed to start a reaction).

4. Check for Understanding With your partner, label the products, reactants, activation energy, progress of reaction, and free energy on the image below. Question: Using this image, what is one thing that the enzyme does in this reaction?

5. Enzyme-Substrate Complex Substrate is the substance an enzyme acts on and is specific for each enzyme Active site is the region of the enzyme that binds to the substrate Enzyme Substrate Active Site

6. Lock-and-Keys Model Enzyme may be used again Enzyme- substrate complex E S P E E P Reaction coordinate

7. Lock-and-Keys Model Keys = Substrates (multiple can bind to each enzyme) Lock = Active Site on the Enzyme As a result of the reaction, the products change shape After the reaction is complete, the substrates are released, freeing up the enzymes to bind with more substrate

8. Check for Understanding With your partner, using what we just discussed, fill in the boxes on the diagram below. Include the name of the part of the enzyme or substrate, and the events that are taking place for the boxes labeled #1-4.

9. Active Site Enzyme Substrate matching the enzyme approaches the active site The substrate bonds to the active site forming the enzyme- substrate complex Product The products formed are released and the enzyme is free to bind to a new substrate The enzyme speeds up the reaction, changing the shape of the substrate

10. Induced Fit 10 changeconfigurationenzyme’s active siteA change in the configuration of an enzyme’s active site (H+ and ionic bonds are involved). Inducedsubstrate.Induced by the substrate. Enzyme Active Site substrate induced fit

11. Factors that Impact Enzyme Function Temperature pH Substrate Concentration Inhibitors

12. Temperature Enzymes move faster as temperature increases Above optimum temperature, the enzyme denatures – preventing it from binding with the substrate Temperature / °C Enzyme activity 0 1010 2020 3030 4040 5050 Denaturation

13. pH Extreme pH will result in denaturation Enzyme structure changes Substrate will no longer fit pH levels different for different enzymes Optimum pH values Enzyme activity Trypsin Pepsin pH 1 3 5 7 9 11

14. Substrate Concentration More substrate causes the substrate to use up the available enzyme faster Once all of the enzyme is bound, the reaction will slow and move at a constant state

15. Competitive Inhibitors Chemicals that resemble an enzyme’s normal substrate and compete with it for the active site Enzyme Substrate

16. Noncompetitive Inhibitors Chemicals that bind to part of the enzyme (not the active site), resulting in changing the shape of the active site  prevents the substrate from binding Enzyme active site altered Noncompetitive Inhibitor Substrate