What’s an Enzyme?
1. Enzymes are proteins.
2. Enzymes are catalysts.• Catalysts speed up chemical reactions• End in –ase (Ex: sucrase, catalase)
Without an enzyme!
With an enzyme!
WARNING• Superman had Kryptonite• Ms. Reed had AP Calculus• Enzymes have
1. Acids & Bases (pH)2. Cold Temperatures3. Extreme Hot Temps
Chemical Reactions
Reactants → (yield) Products
Ex: Fe + O2 → rust
Energy-Absorbing Reaction Energy-Releasing Reaction
Products
Products
Activation energy
Activation energy
Reactants
Reactants
There are 2 kinds of chemical reactions
Anabolic Reactions
Catabolic Reactions
All chemical reactions require a certain amount of energy to get started.
- This is called the… ACTIVATION ENERGY
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Why do we need Enzymes?• Speed up rate of chemical reaction by lowering
the activation energy (energy needed to start chemical reaction)
Without enzyme
Reactants
With enzyme
Activation energywithout enzyme
ActivationEnergy with enzyme
Products
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How do ENZYMES work?1. The enzyme attaches to reactants 2. The reactants that bind to the enzyme
are known as the substrates. 3. The part of the enzyme where the
substrate attaches to the enzyme is called the active site.
4. The shape of the active site only fits the shape of the substrate, like a lock fits a key. Only the correct substrate binds to the enzyme.
Reactants/
Substrates
Enzyme
Lock-and-Key Mechanism- Enzymes can only bind to certain substrates
How do you speed up enzymes?
1. Add more of the enzyme.
2. Warm up the enzyme! Don’t warm it too much or something may happen
Once the enzyme and substrate are together, the enzyme holds the substrate so the reaction can occur. Once the reaction is over, the enzyme unlocks the product and the enzyme can start a new reaction with an identical substrate.
Enzymes are not permanently changed or used up in reactions
A change in the pH of the enzyme can cause a change in the shape of the active site, therefore changing the activity of the enzyme.