Kanamycin A

Serious side effects include ringing in the ears or loss of hearing, toxicity to kidneys, and allergic reactions to the drug.[8]

Other side effects include:[6]

Gastrointestinal effects

• Nausea, vomiting, diarrhea

Musculoskeletal effects

• Myasthenia gravis

Neurologic effects

• Headache
• Paresthesias
• Blurring of vision
• Neuromuscular blockade

Metabolic effects

• Malabsorption syndrome

Kanamycin works by interfering with protein synthesis. It binds to the 30S subunit of the bacterial ribosome. This results in incorrect alignment with the mRNA and eventually leads to a misread that causes the wrong amino acid to be placed into the peptide. This leads to nonfunctional peptide chains.[9]

Kanamycin is a mixture of three main components: kanamycin A, B, and C. Kanamycin A is the major component in kanamycin.[10] The effects of these components do not appear to be widely studied as individual compounds when used against prokaryotic and eukaryotic cells.

While the main product produced by Streptomyces kanamyceticus is kanamycin A, additional products are also produced, including kanamycin B, kanamycin C, kanamycin D and kanamycin X.

The kanamycin biosynthetic pathway can be divided into two parts. The first part is common to several aminoglycoside antibiotics, such as butirosin and neomycin. In it a unique aminocyclitol, 2-deoxystreptamine, is biosynthesized from D-glucopyranose 6-phosphate in four steps. At this point the kanamycin pathway splits into two branches due to the promiscuity of the next enzyme, which can utilize two different glycosyl donors - UDP-N-acetyl-α-D-glucosamine and UDP-α-D-glucose. One of the branches forms kanamycin C and kanamycin B, while the other branch forms kanamycin D and kanamycin X. However, both kanamycin B and kanamycin D can be converted to kanamycin A, so both branches of the pathway converge at kanamycin A.[11]

Kanamycin is used in molecular biology as a selective agent most commonly to isolate bacteria (e.g., E. coli) which have taken up genes (e.g., of plasmids) coupled to a gene coding for kanamycin resistance (primarily Neomycin phosphotransferase II [NPT II/Neo]). Bacteria that have been transformed with a plasmid containing the kanamycin resistance gene are plated on kanamycin (50-100 ug/ml) containing agar plates or are grown in media containing kanamycin (50-100 ug/ml). Only the bacteria that have successfully taken up the kanamycin resistance gene become resistant and will grow under these conditions. As a powder, kanamycin is white to off-white and is soluble in water (50 mg/ml).

At least one such gene, Atwbc19[12] is native to a plant species, of comparatively large size and its coded protein acts in a manner which decreases the possibility of horizontal gene transfer from the plant to bacteria; it may be incapable of giving resistance to bacteria even if gene transfer occurs.

The selection marker kanMX is a hybrid gene consisting of a bacterial aminoglycoside phosphotransferase (kan^r from transposon Tn903) under control of the strong TEF promoter from Ashbya gossypii.[13][14]

Mammalian cells, yeast, and other eukaryotes acquire resistance to geneticin (= G418, an aminoglycoside antibiotic similar to kanamycin) when transformed with a kanMX marker. In yeast, the kanMX marker avoids the requirement of auxotrophic markers. In addition, the kanMX marker renders E. coli resistant to kanamycin. In shuttle vectors the KanMX cassette is used with an additional bacterial promoter. Several versions of the kanMX cassette are in use, e.g. kanMX1-kanMX6. They primarily differ by additional restriction sites and other small changes around the actual open reading frame.[13][15]