Chapter 4 - Enzyme inhibitors and cofactors

Question 1

what are inhibitors

Answer 1

molecules that prevent or slow down the work of enzymes

Question 2

what are the two types of inhibitors

Answer 2

competitive and non-competitive

Question 3

what is the difference between the two types of inhibitors

Answer 3

competitive inhibitors bind to the active site or part of it. they block the substrate binding to the enzyme. non-competitive inhibitors bind to the allosteric site (not the active site) and changes the shape of the protein altering the shape of the active site s the substrate cannot bind

Question 4

name a competitive inhibitor

Answer 4

statins - prescribed to reduce blood cholesterol concentration

Question 5

what is end-product inhibition

Answer 5

when the product of the reaction catalysed by the enzyme also acts as an inhibitor - this stops too much product being made (non-competitive reversible inhibition)

Question 6

what is a cofactor

Answer 6

a molecule that is not part of the protein but is attached to help the enzyme function (organic cofactors and called coenzymes)

Question 7

what is the cofactor in amylase

Answer 7

a chloride ion which forms part of the active site

Question 8

what are many coenzymes derived from

Answer 8

vitamins

Question 9

what other example is there of cofactors

Answer 9

prosthetic groups like in haemoglobin and the zinc in carbonic anhydrase

Question 10

what is the inactive form of enzymes called

Answer 10

precursor enzymes (they often need to undergo a change to become active)