Enzyme Action
- Created by: chickpeatweet
- Created on: 23-09-14 13:58
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- Enzyme Action
- Enzymes lower the Activation Energy
- This energy starts the reaction
- This allows reactions to take place at lower temperature
- Eg. Body Temperature
- Enzyme Structure
- Enzymes are globular proteins
- The primary structure of the enzyme determines it's 3D shape
- The small part of the enzyme which is functional is called the active site
- How they work
- The molecule the enzyme acts on is called the substrate
- Substrate combines with the enzyme
- Enzyme-substrate complex
- Bonds around active site hold substrate in place
- Models
- Lock and Key
- Each enzyme specific shape for each substrate
- Rigid shape
- Induced fit
- The enzyme doesn't have a fixed shape
- Moulds itself around the substrate whilst keeping basic shape
- Lock and Key
- Measuring Enzyme Action
- Measure time-course
- How long event takes
- Usually measure formation of products or disappearance of substrate
- Measure time-course
- Factors which Affect Enzyme Action
- Temperature
- Higher temperature increases kinetic energy
- More collisions
- Once past optimum temp. weak bonds in enzyme break
- Very high temp. can cause denature
- Higher temperature increases kinetic energy
- pH
- Measure of hydrogen ions concentration
- Changes charges on amino acids around active site
- Can break bonds in enzyme structure
- Substrate concentration
- First increases rate of reaction - more collisons
- At a certain concentration, ROR stays constant - excess substrate to empty active sites
- Temperature
- Inhibition
- Competitive inhibitors
- Binds to active site as have similar shape to substrate
- Slows down rate of reactions
- Non-competitive inhibitors
- Attach themselves to a site which is not active
- Changes the shape of active site
- Not affected by substrate concentration
- Competitive inhibitors
- Enzymes lower the Activation Energy
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