Factors affecting enzyme activity
- Created by: jessicawarren
- Created on: 17-03-16 12:22
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- Factors Affecting Enzyme Activity
- Temperature
- Rise provides more kinetic energy to enzyme
- Too much of a rise causes bonds in enzyme to break
- Active site will change shape, enzyme and substrate no longer bind
- Enzyme is denatured
- pH
- Optimum pH 7 for most enzymes
- Pepsin works best at pH 2- found in stomach
- Above/below optimum pH, H+/OH- ions can affect ionic/hydrogen bonds of tertiary structure
- Enzyme denatures
- Enzyme Concentration
- More enzyme molecules, more collisions, more E-S complexes formed
- When substrate runs out, adding more enzyme has no further effect
- Substrate Concentration
- Higher substrate concentration, more collisions, faster ROR.
- Reaches 'saturation' point: when all active sites are full, adding substrate has no further effect
- Decreases with time, so ROR will also decrease. Makes initial ROR highest,
- Competitive Inhibition
- Inhibitors have similar shape to substrate
- Compete to bind to active site
- Block active site so no other substrates can fit in
- Can be overcome by adding substrate
- Non-Competitive Inhibition
- Bind to enzyme at spot other than active site
- Causes active site to change shape
- Substrate can no longer bind
- Not overcome by increasing substrate concentration
- End Product Inhibition
- After reaction has completed, product molecules can stay tightly bound to enzyme
- Enzyme cannot form more of product than cell needs. Example of neg feedback
- Temperature
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