Thread Structures Flashcards
1
Q
How does the structure of methotrexate differ from that dihydrofolate?
A
- No Hydrogen on far left Nitrogen in ring structure. 2. Ketone in far left ring replaced with NH2 group (and now a double bond in ring structure) 3. No hydrogen on bottom N on righthand ring of far left structure (and now another double in ring structure). 4. Methyl instead of hydrogen on central linking Nitrogen.
2
Q
What are the mechanisms of resistance to methotrexate?
A
- Mutations to DHFR enzyme, modifies the folate-binding site so that methotrexate no longer binds. 2. Mutli-drug resistance phenotype due to active efflux of drug. 3. Mutations to the reduced folate carrier which prevent methotrexate uptake.
3
Q
A
Lipophillic antifolate - enter cells by passive diffusion
4
Q
A
5
Q
A
6
Q
A
7
Q
A
8
Q
Lipophillic antifolates
A
9
Q
pyrimidine antagonists
A
5-FU
FdURD
Azacytidine
10
Q
Azacytidine
A
11
Q
How does azacytidine differ in structure to cytidine?
A
