Erythromycin acts by binding to SOS and interferes with______ step of protein synthesis by bacteria?
Ans. D. Translocation. (Ref. KDT 6th/pg. 727).KDT6th/pg. 727......."Erythromycin acts by inhibiting bacterial protein synthesis. It combines with SOS ribosome subunits and interferes with 'translocation'"Erythromycin:# It is bacteriostatic at low but cidal at high concentration.# It is several fold more active in alkaline medium, because the non-ionized form of the drug is favored at higher pH.# MOA:- Erythromycin acts by inhibiting bacterial protein synthesis. It combines with 50S ribosome subunits and interferes with 'translocation'. After peptide bond formation between newly attacjed amino acid and the nacent peptide chain at the acceptor (A) site the elongated peptide is translocated back to peptidyl (P) site, making the A site available for next aminoacyl tRNA attachment. This is prevented by erythromycxin and the ribosomes fail to move along the mRNA to expose the next codon.# Spectrum:- Narrow- Includes mostly gram + and few gram negative bacteria, and overlaps considerably with that of penicillin G.- Highly active against Str. Pyogenes and Str. Pneumoniae, N.gonorrhoea, Clostredia, C. diphtheriae, Listeria.- Most penicillin-resistant staphylococci and streptococci have now become resistant to erythromycin.- Campylobacter, Legionella, Branhamella cataralis, Gadnerella vaginalis and mycoplasma are highly sensitive to erythromycin.# Pharmacokinetics:- 70-80% plasma protein bound, partly metabolized, and excreted primarily in bile in active form.- Renal excretion is minor.- Dose need not be altered in renal failure.# Interaction:- Inhibits hepatic oxidation of many drugs.- Causes rise in plasma levels of theophylline, carbamazepine, valproate, ergotamine, and warfarin.- Cases of QT prolongation, serious V'tachs and death reported due to CYP3A4 inhibition by erythromycin/ clarithromycin resulting in high bloofd levels of concurrently administered terfenadine, astemizole or cisapride.
Transcription
Translation
Transduction
Translocation
Anti Microbial