antivirals

Question 1

mechanism of action nucleoside reverse transcriptase inhibitors

Answer 1

reverse transcriptase enzyme embed NRTI into the synthesised molecule of DNA thus natural nucleosides can no longer be added to the growing viral chain and is terminated in a process called chain termination
EXAMPLES: deoxythymidine, zidovudine

Question 2

NRTIs physiochemistry

Answer 2

using the enzyme thymidine kinase nucleosides transform to nucleoside monophosphate > diphosphate > triphosphate

Question 3

non-nucleoside reverse transcriptase inhibitors

Answer 3

• allosteric inhibitors
• bind to lipophilic pocket at the base of reverse transcriptase enzyme
• prevents the enzyme from allowing single strand of RNA to be transcribed
• prevents replication and protects CD4 cells (helper t-cells)
  EXAMPLE: nevirapine

Question 4

protease inhibitors

Answer 4

• protease cleaves larger proteins into small proteins to make virion
• hydrolysis of proteins peptide bond
• HIV protease cleaves N-terminal to proline residues
• Tyr-Pro identified as cleavage site for HIV protease
• mimic substrate with non hydrolysable functionality
  EXAMPLES: saquinavir, ritonavir, indinavir