Title Chemotherapeutic drugs 2.pptx ✅

Some drugs bind to the 30S (small) subunit, others attach to the 50S (large) ribosomal subunit. Several different steps in the protein synthesis mechanism can be affected: aminoacyl-tRNA binding, peptide bond formation, mRNA reading, and translocation. For example, fusidic acid binds to EF-G and blocks translocation, whereas mucopirocin inhibits isoleucyl-tRNA synthetase Drugs that inhibit nucleic acid synthesis or damage cell membranes - not as selectively toxic as other antibiotics. procaryotes and eucaryotes do not differ as greatly with respect to nucleic acid synthetic mechanisms or cell membrane structure.
Examples of drugs - quinolones and polymyxins. Quinolones inhibit the DNA gyrase and thus interfere with DNA replication,repair,and transcription. Polymyxins act as detergents or surfactants and disrupt the bacterial plasma membrane. Several valuable drugs act as antimetabolites: they block the functioning of metabolic pathways by competitively inhibiting the use of metabolites by key enzymes. Eg Sulfonamides and several other drugs inhibit folic acid metabolism. Sulfonamides (e.g.,sulfanilamide,sulfamethoxazole,and sulfacetamide) have a high therapeutic index because humans cannot synthesize folic acid and must obtain it in their diet. Most bacterial pathogens synthesize their own folic acid and are therefore susceptible to inhibitors of folate metabolism. Antimetabolite drugs also can inhibit other pathways. For example,isoniazid interferes with either pyridoxal or NAD metabolism.