Chemotherapy Flashcards
Beta lactams (penicillin)
Ring is similar to D-ala-D-ala
Forms covalent bond with transpeptidase but doesn’t liberate it
Only bactericidal in proliferating cells
Vancomycin
Cup fits around D-ala-D-ala forming 5 H bonds and causing steric hinderance for transglycosylation
Fosfomycin
PEP analogue
Inhibits pyruvile transferase (For making NAM)
Cycloserine
Inhibits synthesis and linking of D-ala
Must cross cell membrane to do this in cytoplasm
Bacitracin
Binds bactoprenol monophosphate (membrane carrier) to deplete cycle of lipid career
Valinomycin
Makes ion channel to dissipate PMF via K+ movement
Polymyxin antibiotics
Bind gram -ve envelop to make it leaky
Tetracyclines
Bind 16S rRNA in 30S
Inhibit aminoacyl tRNA from entering A site
Bacteriostatic
Aminoglycosides (streptomycin, gentamicin)
Binds 30S; freezes pre-imitation complex so bacteriostatic
+ causes mRNA misreading to make toxic peptides; bactericidal
Erythromycin
Binds 50S at exit tunnel to stop synthesis
Bacteriostatic (mostly)
Chloramphenicol
binds 50S to stop peptidyl transferase; time critical infections only as very toxic
NB: can’t use with erythromycin as they have overlapping binding sites
Fusidic acid
inhibits elongation factor G
Fluoroquinolones (ciprofloxacin for anthrax, Levofloxin for strep pneumonia)
Target GyrA and B to cause bactericidal DNA fragmentation
Rifampicin
Blocks elongation of RNA at initiation stage (via binding beta subunit of DNA dependent RNA pol)
Used for TB
Aminocuomanis and Nalidixic acid
Inhibit DNA gyrase II via Gyrus B
Daunomycin
Intercalates between nucleases to increase DNA length to cause local unwinding
Bleomycin
Intercalated in DNA and if binding reduced metals can react to give superoxide to cleave DNA
Mitomycin C
alkylating; cross links between guanines
Sulfamethoxadole
inhibits DHPS in folate synthesis
Trimethoprim
inhibits DHFR in folate synthesis
Amphotericin B
makes ion channels in ergosterol membranes
Micanozol
inhibits ergosterol biosynthesis
Chloroquinone
inhibits detoxification of haem in malaria so get lots of ROS
Artemisinin
anti-malaria
Makes ROS
Sulfadoxine
inhibits DHPS (malaria)