1. Proteins

2. Protein Basics Made of C,H,O, N CHONPS Monomers = amino acids
- 20 different types of amino acids used to make proteins
The bonds between amino acids are called peptide bonds so…
Proteins are polymers that
are also called
Polypeptides.

3. Meet the monomer –Amino acid
3 main parts
- Amino group NH2
- Carboxyl group COOH
- R group (side chain)
each of the 20 types
of amino acids have
a unique R group

5. Proteins form from chains of amino acids
Proteins vary in length – can be 1,000s of amino acids long
Protein

6. Proteins Shape
A protein’s shape is determined by the order that amino acids are joined in
The shape of a protein determines its function
Hemoglobin antibody enzymes polymerase

7. Protein Structure – Primary Structure
Primary structure is the order of the amino acids that make up a protein.
- the interactions of the R groups on each amino acid
cause the molecule to bend and fold – different arrangements create different shapes
- as a result- the order of
amino acids determines
the shape of the protein
- shape determines function
- changing a single amino acid can change a protein’s
shape.

8. Enzymes: “Helper” Protein molecules

9. Chemical reactions of life
Processes of life
building molecules
synthesis
breaking down molecules
digestion + +

10. Nothing works without enzymes!
How important are enzymes?
all chemical reactions in living organisms require enzymes to work
building molecules
synthesis enzymes
breaking down molecules
digestive enzymes
enzymes speed up reactions
“catalysts”
enzyme +
enzyme
We can’t live without enzymes! +

11. Enzymes A protein catalyst
Enzymes are important proteins found in living things. An enzyme is a protein that changes the rate of a chemical reaction.
They speed up metabolic reactions.

12. Examples
synthesis
enzyme +
digestion
enzyme +

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

14. Enzymes aren’t used up Enzymes are not changed by the reaction
used only temporarily
re-used again for the same reaction with other molecules
very little enzyme needed to help in many reactions
substrate
product
active site
enzyme

15. It’s shape that matters!
Lock & Key model
shape of protein allows enzyme & substrate to fit
specific enzyme for each specific reaction

16. 2 1 3

17. 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

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

19. 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!

20. Temperature Effect on rates of enzyme activity Optimum temperature
greatest number of collisions between enzyme & substrate
human enzymes
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

21. Temperature 37° human enzymes reaction rate temperature
What’s happening here?!
37°
reaction rate
temperature

22. pH 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

23. 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

24. Two examples of Enzyme Inhibitors
a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.
Enzyme
Substrate
Competitive inhibitor

25. Inhibitors b. Noncompetitive inhibitors:
Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn alters the active site.
Enzyme
Noncompetitive
Inhibitor
Substrate
active site
altered

26. For enzymes… What matters?
SHAPE!