Factors affecting enzyme activity
- Created by: ellabella7500
- Created on: 17-10-16 16:22
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- Factors Affecting Enzyme Activity
- Temperature
- 1. An increase in temperature makes enzymes vibrate more
- 2. If the temperature goes above a certain level the bonds between the enzymes are broken - the enzyme loses its shape
- 3. The active site changes shape, which means the substrate no longer fits when the temperature gets too high
- 4. The enzyme denatures if the temperature is too high
- Substrate Concentration
- 1. An increase in substrate means greater collisions between substrate and enzymes
- This will happen until a saturation point where all the enzymes are used and adding more substrate will make no difference
- pH Levels
- 1. Just like temperature, they have a optimum pH level, which is 7
- 2. However, Pepsin works best at pH 2 as it is found in the stomach
- 3. Enzyme's tertiary structure is held by ionic and hydrogen bonds, which can be altered by pH levels above and below 7
- 4. H+ and OH- ions alter the bonds
- 5. This changes the shape of the active site, making the enzyme denatured
- Enzyme Concentration
- As the enzyme concentration increases the rate of the reaction increases linearly, because there are more enzyme molecules available to catalyse the reaction.
- At very high enzyme concentration the substrate concentration may become rate-limiting, so the rate stops increasing.
- Normally enzymes are present in cells in rather low concentrations.
- Inhibitors
- Inhibitors inhibit the activity of enzymes, reducing the rate of their reactions.
- They are found naturally but are also used artificially as drugs, pesticides and research tools.
- Inhibitors that bind fairly weakly and can be washed out are called reversible inhibitors, while those that bind tightly and cannot be washed out are called irreversible inhibitors.
- Temperature
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