1. ENZYMES

2. Enzymes help with most chemical reactions in the body

3. Digestion requires Enzymes
Amylase in salivary glands
Pepsin in stomach
Lipase and trypsin in small intestine

4. Enzyme supplements

5. Enzymes assist in 2 main type of reactions in cells
Synthesis (make) compounds
2) Decomposition (break) compounds
Both require energy

6. Synthesis using enzyme
A + B + Enzyme = AB + Enzyme

7. Decomposition using enzyme
CD + Enzyme = C + D + Enzyme

8. The enzyme catalase Peroxide kills cells
Catalase aids decomposition of peroxide into water and oxygen in cells
H2O2  H2O and O2

9. Activation energy
Energy required for a chemical reaction to occur

10. Most chemical reactions in cells require too much energy to occur naturally

11. Enzymes
Natural catalysts that lower the activation energy so a reaction can occur in a cell

12. Enzymes are very complex proteins
Proteins are three dimensional

13. Terms Substrate - The molecule that the enzyme attaches to
Active site - The spot on the enzyme that fits into the substrate

14. Enzymes have a specific fit
Like a lock and key

15. Induced fit model
Some enzymes adapt slightly to fit substrate better

16. Enzyme animation Claymation enzyme 30 secs
Pacman Animation 2 mins

17. Enzymes are not used in the reaction
Can keep working! Unless destroyed or denatured
Heat, acid etc. can denature enzymes undoing the tertiary structure

18. Denaturing proteins
Heat etc. will break bonds of protein tertiary structure. reversible

19. Enzyme Regulation Temperature pH Concentration of enzyme or substrate
Inhibitors

20. Effect of TEMPERATURE Increased temperature increases particle motion
This increases reaction rate.
Enzymes work faster with increased temperature
BUT Enzymes are proteins and above a certain temperature they denature (come apart)

21. Every enzyme has an optimal temperature
Increased temperature increases reaction rate until denaturing occurs

22. Effects of pH Changes in pH also denature enzyme
Change in pH change the ionization state of many amino acid R groups
This can alter the active site and keep substrate from binding

23. Enzymes have an optimal pH
Pepsin in stomach
Trypsin in intestine

24. Effect of substrate concentration
Increase in substrate, increases rate until enzymes saturated

25. Law of Mass action Enzyme catalyzed reactions can reverse.
When product becomes more than substrate, reaction can reverse back to substrate
Note: this does not happen in high exergonic reactions, too much energy required to reverse

26. Coenzymes A chemical required by an enzyme for proper functioning
Binds to enzyme temporarily
Coenzyme Q etc.
Many vitamins are Coenzymes

27. Competitive inhibitor
Blocks active site

28. Competitive inhibitor
Slows the rate, but eventually substrate builds up and competitive inhibitor has no effect

29. Non Competitive inhibitor
Attaches to enzyme in another spot which alters its active site

30. Non Competitive inhibitor

31. Allosteric enzymes
Enzymes that can be altered by an non competetive inhibitor
Can also be Promoters! That increase enzyme activity
A product can act as a feedback inhibitor

32. Toxic substances are often enzyme inhibitors
They stop important biological processes
Ex cyanide, lead, mercury, pesticides

33. Peroxidase enzyme Peroxidase catalyses the breakdown of peroxide
turnip peroxidase
2H2O  2H2O + O2
We will use an in our lab

34. Animations of enzymes