Streptomycin stability

He found the order of stability for several drugs in sugar syrup and honey were as follows sulfa drugs > streptomycin > tetracycline > chlortetracycline > erythromycin > oxytetracycline. 

The glycoside/aminoglycoside antibiotics, like the macrolides, exert a bacteriostatic effect due to selective inhibition of bacterial protein synthesis, with the exception of novobiocin (26). The compounds neomycin (27), spectinomycin (28) and streptomycin (29) bind selectively to the smaller bacterial 30S ribosomal subunit, whilst lincomycin (30) binds to the larger 50S ribosomal subunit (cf. macrolides). Apramycin (31) has ribosomal binding properties, but the exact site is uncertain (B-81MI10802). Novobiocin (26) can inhibit nucleic acid synthesis, and also complexes magnesium ion, which is essential for cell wall stability. 

V. Damjanovic, Kinetics of thermal death and prediction of the stabilities of freeze-dried streptomycin-dependent live Shigella vaccines. J. Biol. Stand. 2 297-311, 1974. 

The 30 kDa protein is encoded by nuclear DNA, and precursor protein is transported from cytoplasm to chloroplast. As the protein is located at the lumenal surface of the thylakoid, it must also cross thylakid membrane before it is incorporated into the PS II complex properly. Identification of the precursor protein has been carried out with isolation of mRNA and identification of the translation product. Transit peptide of several kilodalton is shown to be attached to the amino terminal of the mature protein. We tried to identify the precursor protein of the 30 kDa protein with Euglena cells whose chloroplast is functionally inactivated. Treatment of the cells with streptomycin under illumination induced a protein of 36 and 52 kDa which were cross-reactable with the antibody against spinach 33 kDa protein. The proteins were also detected when chloroplast-less mutant was illuminated. The 36 kDa protein is probably a precursor of the 30 kDa protein. The 52 kDa protein was dissociated into 30 kDa protein and some other protein(s) with SDS-PAGE with 8 M urea, and it is possible that we detect a complex form of the precuresor or mature 30 kDa porotein and the protein(s) which may stabilize the free 30 kda protein or assist the 30 kDa protein in transportation across the envelope and/or thylakoid membranes. Analysis is now being carried out to elucidate the characteristics of the precursor proteins. 

That the aldehydo-group of streptomycin does not cyclize with either the methylamino- or the guanidino-groups to form a four-ring structure has been shown by n.m.r. spectroscopy. Instead it is suggested that the group is probably hydrated and stabilized by the C-3 hydroxy-group of L-streptose, ... 

Selection of the specific aminoacyl-tRNA to be bound at the ribosomal A site is by base-pairing between the relevant mRNA codon and the tRNA anticodon. Because this interaction involves only a triplet of bases and hence a maximum of nine hydrogen bonds (see Fig. IB), it is intrinsically unstable at physiological temperatures and is probably stabilized by components of the ribosome to allow sufficient time for peptide bond synthesis to occur. Also, the codon-anticodon pairing must be monitored for fidelity in order to minimize errors in translation. In E. coli there is genetic and biochemical evidence that one of the proteins of the small ribosomal subunit, S12, is involved in ensuring the fidelity of normal translation and in causing the mistranslation which occurs in the presence of the antibiotic streptomycin due to incorrect codon-anticodon interactions. 

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