Enzymes

Question 1

Why are enzyme inhibitors necessary?

Answer 1

• In many biological processes, enzymes function in a negative feedback loop. In this loop, the product of the enzyme will inhibit the enzyme once enough product has been made in order to stop the enzyme from producing more product than what is needed.
• Excess product can be potentially damaging, it is also wasteful.
• The reaction still produces enough product to sustain necessary metabolic requirements.

Question 2

How do competitive inhibitors function?

Answer 2

• Competitive inhibitors compete with the substrate for the active site. The inhibitor molecule has a similar shape to the substrate molecule. When the inhibitor binds, it occcupies the active site without causing a reaction.
• Mostly reversible, bind temporarily. Aspirin is an exception.

Question 3

What is the effect of increasing the substrate concentration in a reaction with a competitive inhibitor?

Answer 3

• Increases the rate of reaction.
• The substrate molecules will outcompete the competitive inhibitor.

Question 4

How do non-competitive inhibitors function?

Answer 4

• They do not bind to the active site. The inhibitor molecule can bind to the allosteric site.
• Causes the tertiary shape of enzyme to change, so AS changes shape.
• The substrate is no longer able to bind to form an enzyme-substrate complex as it is no longer complementary.
• Can be permanent or reversible.

Question 5

What is the effect of increasing the substrate concentration on a reaction with a fixed quantity of non-competitive inhibitor?

Answer 5

• No increase on the rate of reaction.
• They do not compete for the AS.