1.8 Factors affecting enzyme action

Question 1

What are the four factors that affect enzyme reaction?

Answer 1

• temperature
• pH
• Enzyme concentration
• Substrate concentration

Question 2

How does temperature affect enzyme reaction?

Answer 2

• increase in kinetic energy
• increase in effective collisions
• increase rate of reaction
• HOWEVER, after around 60°C enzymes start to denature

Question 3

How does pH affect enzyme reaction?

Answer 3

• A change in pH alters the charge is on the amino acids that make up the active site of the enzyme, resulting in enzyme-substrate complex not being able to be formed
• depending on pH, may cause bonds maintaining tertiary structure to break

Question 4

How does enzyme concentration affect the rate of reaction?

Answer 4

• a proportionate increase of rate of reaction because more active sites will be free for substrates to create an induced fit model
• a graph to show this would eventually level out because all the substrates are in active sites and some active sites will still be free

Question 5

How does substrate concentration affect the rate of enzyme action?

Answer 5

• initially an increased rate of reaction as all active sites will be filled with substrates, however eventually a graph to show this would plateau because all active sites will be filled and excess substrates won’t be able to find any free active sites