Factors Affecting Enzyme Activity Flashcards
What factors affect enzyme activity?
Temperature
pH
Enzyme Concentration
Substrate Concentration
Concentration of Competitive Inhibitors
Concentration of Non-Competitive Inhibitors
How does temperature affect enzyme activity?
Molecules have more energy when temp increases
Makes enzymes more likely to collide with substrate molecules
Collisions happen with greater energy, so reaction is more likely to take place
If temperature is too high (< 37 degrees) particles will vibrate and break
AS changes shape + enzyme denatures
How does pH affect enzyme activity?
All enzymes have an optimum pH (7 for most human enzymes)
Above and below this, ionic + hydrogen bonds in tertiary structure can break
Active site changes shape, so enzymes denature
How does enzyme concentration affect enzyme activity?
More enzymes = more collisions between substrate + enzyme
This causes an increase in ESC = increase in rate of reaction
However, it can only increase to a certain point as substrate concentration then becomes the limiting factor
How does substrate concentration affect enzyme activity?
Increase in substrate concentration = increase in rate of reaction
If too much substrate is present, enzyme concentration becomes the limiting factor
Therefore, enzyme activity can only increase to a certain point
What is an enzyme inhibitor?
A molecule that binds to an enzyme and decreases its activity
How does a competitive inhibitor work?
A competitive inhibitor is of similar shape to the substrate, and is complementary to the active site. They attach to the active site before the substrate thus blocking it, but interact weakly so they dont stay permanently.
How does a non-competitive inhibitor work?
They bind to another binding site other than the active site (allosteric site) and alter the shape of the enzyme so the substrate can no longer bind to the active site.
How would these affect enzyme activity?
They would both decrease the rate of enzyme activity as they are both inhibiting the active site from binding to the substrate and therefore forming enzyme-substrate complexes
