1. 1 Enzymes

2. Apple Experiment Come and get 2 slices of apples ( A & B – keep separate), paper towel and a bottle of lemon juice. When you get back to your seat: 1. Write A & B on paper towel. Place apple A on A side and apple B on B side 2. Immediately squeeze lemon juice over apple slice B. 3. IMPORTANT! Don’t get lemon juice all over both slices. 4. Set your apple slices aside and return the lemon juice bottle. From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com

3. What are enzymes? Enzymes are Proteins ( (tertiary and quaternary structures). Image: Levels of protein structure, M RuizLevels of protein structure From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com

4. Why Are Enzymes So Important? Why are we devoting one whole lecture topic to a protein molecule? Nearly all chemical reactions in biological cells need enzymes to make the reaction occur fast enough to support life. Image: Jumping rope, Meagan E. KleinJumping rope From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com

5. 5 What Are Enzymes? Catalyst.Acts as a Catalyst. A catalyst speeds up a chemical reaction. Not permanentlyNot permanently changed in the process

6. 6Enzymes catalyzeAre specific for what they will catalyze ReusableAre Reusable aseEnd in –ase-Sucrase-Lactase-Amylase

7. 7 How do enzymes Work? weakening bonds which lowers activation energy Enzymes work by weakening bonds which lowers activation energy

8. 8Enzymes Free Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

9. 9

10. fit with substrate like a ____ and ____.Enzymes… From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com

11. 11 Enzyme-Substrate Complex substance enzyme substrate The substance (reactant) an enzyme acts on is the substrate Enzyme Substrate Joins

12. 12 Active Site restricted region enzyme bindssubstrateA restricted region of an enzyme molecule which binds to the substrate. Enzyme Substrate Active Site

13. 13 Enzymes can break apart substances or put substances together.Enzymes can break apart substances or put substances together.

14. 14 What Affects Enzyme Activity? Three factors:Three factors: 1.Environmental Conditions 2.Cofactors and Coenzymes 3.Enzyme Inhibitors

15. 15 1. Environmental Conditions 1. Extreme Temperature are the most dangerous 1. Extreme Temperature are the most dangerous - high temps denature (unfold) enzyme. - high temps may denature (unfold) the enzyme. 2.pH (most like 6 - 8 pH near neutral) 3.Ionic concentration (salt ions)

16. 16 2. Cofactors and Coenzymes Inorganic substances (zinc, iron) vitamins enzymatic activityInorganic substances (zinc, iron) and vitamins are sometimes needed for proper enzymatic activity. Example:Example: Ironhemoglobin pick up oxygen. Iron must be present in hemoglobin in order for it to pick up oxygen.

17. 17 Inhibitors Inhibitors Competitive inhibitors: resemble enzyme’s normal substrate competeactive site Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site. Enzyme Competitive inhibitor Substrate

18. Meet the Enzyme : Catecholase _________ juice and other acids are used to preserve color in fruit, particularly apples, by lowering the ____ and removing the copper (cofactor) necessary for the enzyme to function. Reaction: catecholase catechol + O 2 ----------  polyphenol colorless substrate brown product Images: Apples, T. Port; Lemons, André Karwath; Enzyme with Cofactor, Wiki; pH scale, Edward Stevens, WikiLemonsEnzyme with CofactorpH scale From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com

19. Look at your apple slices Observe and write down any differences in slices. Do you think the lemon juice had an effect on apple? What do you think happened? Please explain. 19

20. Confused? Here are some links to fun resources that further explain enzymes: Enzymes Main Page on the Virtual Cell Biology Classroom of Science Prof Online.Enzymes Science Prof Online “How Enzymes Work” an animation from McGraw-Hill.How Enzymes Work Interactive Enzyme Tutorial and quiz from Life: The Science of Biology.Interactive Enzyme Tutorial “ The Role Enzymes Play in the Body ” from Enzymedica. These guys are selling supplements. I don’t endorse the supplement, but their video is very instructive regarding enzymes and digestion. The Role Enzymes Play in the Body “ Assignment Discovery: Enzyme Catalysts ” from HowStuffWorks, a Discovery Company. Assignment Discovery: Enzyme Catalysts “ Enzymes and Digestion ” from About.com. Enzymes and Digestion “ Bio Rad GTCA Song ” musical advertisement for SsoFast™. Bio Rad GTCA Song And why not sing “ Goodtimes with Enzymes ” to the Chic song “Goodtimes.” See next slide for lyrics.Goodtimes (You must be in PPT slideshow view to click on links.) From the Virtual Cell Biology Classroom on ScienceProfOnline.comVirtual Cell Biology ClassroomScienceProfOnline.com