3.1,2,3,4 Contd: Allosteric Regulation

Question 1

How many binding sites do allosteric enzymes have? What are they?

Answer 1

• 2
• Active site
• allosteric site (regulatory site, site other than active site)

Question 2

What occurs in allosteric regulation?

Answer 2

• molecules bind to an allosteric site (noncovalent interactions) which changes the shape and function of the active site

Question 3

What can allosteric regulation result in? (2)

Answer 3

• inhibition by an inhibitor

- stimulation by an activator of the enzyme’s activity

Question 4

What is an allosteric activator?

Answer 4

• substrate binds to allosteric site and stabilizes the shape of the enzyme so that the active site remains open

Question 5

What is an allosteric inhibitor?

Answer 5

• The substrate binds to allosteric site and stabilize the enzyme shape so that the active sites are closed (inactive form)

Question 6

What occurs in cooperativity?

Answer 6

• The substrate binds to one active site on an enzyme (with more than one active site), which stabilizes the active form

Question 7

What is cooperativity considered allosteric regulation?

Answer 7

• binding at once site change the shape of other sites

Question 8

What occurs in feedback inhibition?

Answer 8

• sometimes, the end product of a metabolic pathway can act as an inhibitor to an early enzyme in the same pathway
• please see diagram