Enzymes Flashcards
What are enzymes?
They are globular proteins that contain an active site that binds to a substrate to hydrolyse it quickly.
What is the function of an enzyme?
It catalyses a reaction by providing an alternative route with a lower activation energy
What is activation energy?
The minimum energy required for a reaction to occur
What is the induced fit model?
- (before reaction) active site not complementary to substrate;
- Shape of active site changes as enzyme-substrate complex forms;
- Stressing/distorting/bending bonds (in substrate leading to reaction);
What is a competitive inhibitor?
Binds to the active site of an enzyme and prevents substrate from binding to it
What is a non-competitive inhibitor?
Binds to the enzyme and changes the enzyme’s shape so the substrate can no longer attach
What 6 factors affect enzyme reactions?
1) Conc. of enzyme
2) Conc. of substrate
3) Temperature
4) pH
5) Competitive Inhibitors
6) Non-competitive inhibitors
What is the effect of a competitive inhibitor on rate of reaction and product produced?
- conc. increases, the product produced also increases
- eventually reach the same amount as without an inhibitor, since the
- increase of substrate means more substrate, so it is more likely to attach to the active site than inhibitor.
What is the effect of a non-competitive inhibitor on rate of reaction and product produced?
This inhibitor will change the shape of the enzyme so very minimal product would be produced, since the enzyme would be denatured.
How does temperature affect the rate of reaction of enzyme activity?
Rate of reaction increases as temp. increases to a point. The optimum temp is 37 degrees, if the temp surpasses this the enzyme denatures.
How does pH affect rate of reaction of enzyme activity?
Optimum pH is different in different parts of the body (e.g. stomach is more acidic), however, generally, when an area is too acidic the enzyme will denature, and if too alkaline the enzyme will also denature.
What can affect pH?
Carbon Dioxide in the blood can increase acidity.
How does enzyme concentration affect rate of reaction?
R.o.r increases with concentration, however the limiting factor would eventually be the substrate conc. Although, the reaction will most likely have finished before this happens.
How do you find rate of reaction on a graph?
Draw a tangent to the curve and calculate the gradient of the tangent
