Molecular Targets

Question 1

Give 6 molecular targets

Answer 1

1. Enzymes
2. Plasma membrane receptors
3. Transporters
4. Ion channels
5. Nucleic acids
6. Nuclear receptors

Question 2

What do statins do?

Answer 2

Inhibit an enzyme involved in the synthesis of cholesterol known as HMG CoA reductase

Question 3

What is a receptor?

Answer 3

Any biomolecule to which a drug binds to induce a biological response.

Question 4

What are the classifications of receptors?

Answer 4

1. Ligand gated ion channels
2. G-protein coupled reeptors
3. Enzyme-linked receptors
4. Intracellular

Question 5

What does methotrexate do?

Answer 5

Mimics the substrate dihydrofolic acid and so binds to it inhibiting the activity. DHFR is required to produce tetrahydrofolic acid which is needed for synthesis of purines and pyrimidines. Affects most rapidly dividing cells

Question 6

What does timethoprim do?

Answer 6

Another dihydrofolate inhibitor, used to treat bacterial infections of the urinary tract. Inhibits bacterial DNA synthesis, higher affinity for bacterial dihydrofolate reductase.

Question 7

What doe blocking the enzyme HIV proteinase do?

Answer 7

Slows down viral reproduction, HIV proteinase binds and cleaves coat peptides required for making new viruses.

Question 8

Give three examples of drugs which target enzymes?

Answer 8

1. Methanotrexate
2. trimethoprim
3. Drugs which block HIV proteinase

Question 9

What are COX-1 and COX-2?

Answer 9

Cyclooxygenases, -membrane-bound proteins that catalyse prostaglandin synthesis

Question 10

What sort of drugs block cyclooxygenases?

Answer 10

Ibuprofen and aspirin

Question 11

What is special about aspirin?

Answer 11

It covalently modifies, its mechanism of action is similar to its metabolism, it acetylates Ser-530 and releases salicylic acid.

Question 12

What does the drug neostigmine target?

Answer 12

Acetylcholinesterase. Allows acetylcholine to build up

Question 13

Name three drugs which target membrane-bound enzymes

Answer 13

1. Ibuprofen
2. Aspirin
3. Neostigmine

Question 14

What receptor does salbutamol target?

Answer 14

B2- adrenergic receptor, for treating asthma, relaxes bronchiolar muscle.

Question 15

What is the effect of candasartan and what does it target?

Answer 15

Reduces blood pressure

Angiotensin AT1

Question 16

Which dopamine transporter does cocaine bind to?

Answer 16

DAT on the presynaptic membrane resulting in a build up of dopamine

Question 17

What do sertraline and fluoxetine target?

Answer 17

Serotonin - SSRIs

Question 18

What does dapagliflozin (Forxiga) target?

Answer 18

Sodium dependant glucose co-transporters by blocking them in the kidney and preventing reuptake of filtered glucose.

Question 19

What does glipizide block?

Answer 19

ATP sensitive K+ channels resulting in depolarisation of the membrane and influx of Ca2+ leading to insulin release. Treats type 2 diabetes.

Question 20

What does Diazepam target?

Answer 20

GABAa

Treat anxiety, is an allosteric modulator

Question 21

Give two drugs which target nucleic acids

Answer 21

Actinomycin D and Tamoxifen

Question 22

What does actinomycin D do?

Answer 22

Contains a flat ring system that can intercalate between the bases in DNA, preventing the transit of RNA polymerase and therefore inhibiting transcription.