Enzymes as drug targets

Question 1

Example and use of ACE inhibitors

Answer 1

Captopril, rampiril in high BP, HF and chronic renal insufficiency

Question 2

What is Km?

Answer 2

Substrate conc where reaction rate reaches half of Vmax

Question 3

Competitive inhibitor?

Answer 3

Competes with substrate for active site

Question 4

Reversible inhibitor

Answer 4

Overcome by increase in substrate, Km up but Vmax same

Question 5

Irreversible inhibitor

Answer 5

Covalent binding, renders active site unusable, decreases Vmax

Question 6

Example of irreversible inhibitor

Answer 6

Selegiline, irreversible inhibitor of MAO B

Question 7

What does a false substrate do plus example?

Answer 7

Produces false transmitter, alpha methyl dopa

Question 8

Example of pro drug

Answer 8

L-DOPA in Parkinson’s

Question 9

Drugs acting on Ach

Answer 9

Neostigmine and echothiopate

Question 10

Drug that acts on Choline acetyl transferase

Answer 10

Hemicholinum (f5)

Question 11

Drug acting on bacteirial transpeptidases

Answer 11

Penicillin

Question 12

Drug acting on Xanthine Oxidase

Answer 12

Allopurinol

Question 13

Drugs acting on MAO

Answer 13

Selegiline, ipronazid

Question 14

Drug acting on dihydrofolate synthase

Answer 14

Sulphonamides

Question 15

Drugs acting on dihydrofolate reductase

Answer 15

Methotrexate

Question 16

Drugs acting on dopa decarboxylase

Answer 16

Carbidopa, alpha methyl dopa

Question 17

Drugs acting on reverse transcriptase

Answer 17

Zidovudine

Question 18

Drugs acting on thymidine kinase

Answer 18

Aciclovir

Question 19

How does Cox 1 work

Answer 19

Constitutive, concerts arachidonate to cyclic endoperoxidases -> prostanoids inc thromboxane and prostaglandin

Question 20

How does cox 2 work

Answer 20

Inducible by injury or inflammation

Question 21

What do NSAIDs inhibit

Answer 21

Cox 1 and 2, lasts until new enzyme synthesised

Question 22

How do sulphonamides work?

Answer 22

Compete with PABA for uptake in bacteria, prevent DNA synthesis by inhibiting dihydrofolate synthase

Question 23

Example and use of HMG CoA reductase inhibitor

Answer 23

Pravastatin in hypercholesterolaemia