Factors affecting enzyme activity

HideShow resource information
View mindmap
  • 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.


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Biological molecules, organic chemistry and biochemistry resources »