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.