G-418 disulphate 5 g

G-418 is an aminoglycoside antibioticum and is applied as a selective agent in transformation experiments. The antibioticum binds to the 30S subunit of the prokaryotic ribosome. thereby inhibiting protein synthesis as well as generating errors in the transcription of the genetic code. Ribosomes of mitochondria and chloroplasts of higher plants are related to bacterial ribosomes and are also susceptible to aminoglycosides. Being a derivative of gentamycin. the antibioticum contains a additional 3OH that can be phosphorylated by NPT II. As a result of this phosporylation. the charge and the steriometric conformation of the G-418 molecule changes in such a way that the antibioticum is no longer capable of binding to the specific ribosome binding sites.G-418 is used as an alternative for kanamycin in monocots. e.g.. rice. Lolium. Graminea which are highly resistant to the latter. In all cases G-418 was shown to be more effective. This is most probably due to the better binding characteristics of the gentamycine shaped structure of G-418.