Streptomycin is classified chemically as an aminoglycosidic antibiotic and some of the other aminoglycosides include kanamycin, neomycin, tobramycin and amikain. In general all aminoglycoside make use of their inhibitory action by blocking protein synthesis in bacteria. Streptomycin kills bacteria by inhibiting protein synthesis by combining irreversibly with the 30S subunit of the70S ribosomes, found typically in prokaryotes. To be more specific, it binds with the S12 protein which is involved in the initiation of protein synthesis.
Researchers have found through experiments that streptomycin stops the initiation of protein synthesis by blocking the binding of initiator N-formylmethionine tRNA to the ribosome. Besides, Streptyomycin is also known to stop the normal dissociation of 70S ribosomes into their 50S and 30S subunits. Therefore formation of polysomes is inhibited. Streptomycin action involves distorting the ribosome so that transition from initiation complex (30S-mRNA-tRNA) to chain elongating ribosome is blocked. As a result of this the normal sequence of translation is disrupted and the bacteria is unable to synthesize proteins which is vital for its cell growth and thereby fails to survive. Studies also have shown that the drug also disrupts the cell membrane of susceptible bacteria.
Over the years many bacterial species, such as Bacillus subtilis Strain S