1.8 Factors Affecting Enzyme Action Flashcards
What are the 5 factors which affect Enzyme Action
1) Substrate Concentration
2) Enzyme Concentration
3) pH
4) Temperature
5) Inhibitors
What do optimal conditions do?
Give the greatest rate of enzyme activity.
What happens to the rate of enzyme action when the temperature increases until it’s optimum?
Increasing the temp increases the Kinetic energy
This increased KE results in an increased number of collisions
This increases the chance of the formation of a stable ES-complex
Increase the rate of reaction
What happens when the rate of enzyme action when the temperature increases past the optimum?
Increased temperature vibrates molecules violently
This breaks hydrogen bond and other cohesive forces
This alters the 3D shape of the enzyme
The active site can no longer form a stable enzyme substrate complex
The Enzyme is DENATURED
What does the pH of a substance refer to?
The pH depends on the concentration of H+ and OH- ions
Do different Enzymes have different optimum pH’s
Yes
The pH does what to enzymes?
What do the ions do
The ions either:
1) Alter the charges on the amino acids in the active site so the substrate can no longer bond and form a stable ES-complex
2) Break bonds (hydrogen and ionic) in the tertiary structure of the enzyme so the active site changes shape (DENATURED)
What pH do intracellular enzymes work best at?
7.3-7.45
What pH do extracellular enzymes work best at? (E.g. digestive system)
Extreme pH
What is the effect of substrate concentration in the rate of reaction?
The RoR increases as the substrate concentration increases, until the enzyme is working at full capacity… the point of saturation.
This is due to increased collisions between the enzyme and substrate.
What do inhibitors do?
Inhibitors can slow done or stop the catalytic activity of enzymes by affecting their ability to bind to substrates.
Why do cells produce enzyme inhibitors?
To control the rate of reactions…
To reduce the build up of unneeded/damaging goods
To reduce dangerous action to the cell itself(protein digestion)
To stop the wasting of resources
What are the two types of inhibitor?
1) competitive
2) non-competitive
What is the difference between competitive and non-competitive inhibitors?
Competitive inhibitors:
Binds to the active sister
Non-competitive inhibitors:
DOESN’T bind to the active site (bonds to an allosteric site instead)
What do competitive inhibitors do?
Competitive inhibitors are a very nearly complementary shape for the Active site
They will bind- blocking the active site- then fall free
They decrease the RoR as when they bind, the AS is blocked and there is less chance that a substrate can bind.
