1. Enzymes: “Helper” Protein molecules (Proteins in the body coded from DNA sequence)

2. How important are enzymes?
All chemical reactions require enzymes
building molecules
synthesis enzymes
breaking down molecules
digestive enzymes
enzyme +
We can’t live without enzymes!
enzyme +

3. How They work: lower activation energy

4. Definition
Biological catalysts that speed up chemical reactions

5. Examples
synthesis
enzyme +
digestion
enzyme +

6. Enzymes are proteins
Each enzyme is the specific helper to a specific reaction
right shape for the job
Examples sucrase breaks down sucrose
proteases breakdown proteins
lipases breakdown lipids
DNA polymerase builds DNA
Oh, I get it!
They end in -ase
Sometimes named for the reaction they help

7. Enzymes aren’t used up
Enzymes - not changed by the reaction
re-used many times for the same reaction with other substrate molecules (10 million H2O2/hydrogen peroxide molecules broken down per second!)
substrate
product
active site
enzyme

8. It’s shape that matters!
Lock & Key model
Allow substrate to fit
specific enzyme for each reaction

9. 2 1 3

10. Enzyme vocabulary Enzyme Substrate Products Active site
helper protein molecule
Substrate
molecule that enzymes work on
Products
what the enzyme helps produce from the reaction
Active site
part of enzyme that substrate molecule fits into

11. What affects enzyme action
Correct protein structure
correct order of amino acids
why? enzyme has to be right shape
Temperature
pH (acids & bases)

12. Order of amino acids Wrong order = wrong shape = can’t do its job! DNA
folded protein
chain of amino acids
DNA
right shape!
folded protein
chain of amino acids
DNA
wrong shape!

13. Temperature Effect on rates of enzyme activity
Optimum greatest # of collisions between enzyme & substrate
Human: 35°- 40°C (body temp = 37°C)
Raise temperature (boiling)
denature protein = unfold = lose shape
Lower temperature T°
molecules move slower
fewer collisions between enzyme & substrate

14. Temperature human enzymes 37 Degrees Celsius = Body temperature 37°
What’s happening here?!
37°
reaction rate
temperature
37 Degrees Celsius =
Body temperature

15. pH (Power of hydrogen) Effect on rates of enzyme activity
changes in pH changes protein shape~ Denatures
most human enzymes = pH 6-8
depends on where in body
pepsin (stomach) = pH 3
trypsin (small intestines) = pH 8

16. pH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 stomach pepsin intestines trypsin
What’s happening here?!
reaction rate 1 2 3 4 5 6 7 8 9 10 11 12 13 14 pH

17. For enzymes… What matters?
SHAPE!