- Kanamycin is an aminoglycoside antibiotic that inhibits bacterial protein synthesis by binding to the 30S subunit of prokaryotic ribosomes, causing misreading of mRNA and the production of dysfunctional proteins. Though widely used in molecular biology—particularly in bacterial selection for kanamycin resistance genes in plasmids—kanamycin is less commonly used in mammalian cell culture compared to antibiotics like gentamicin or penicillin-streptomycin.
- In the context of cell culture, kanamycin can be used to suppress Gram-negative bacterial contamination, but its utility is limited because its spectrum of activity is narrower, and it tends to be more cytotoxic to mammalian cells than gentamicin at comparable concentrations. This higher toxicity is attributed to possible off-target interactions with mitochondrial ribosomes, which resemble bacterial ribosomes in structure and function. As a result, kanamycin may disrupt mitochondrial protein synthesis and impair cellular respiration or viability, especially at higher concentrations or in sensitive cell types.
- When kanamycin is used in eukaryotic cell culture, it is typically at concentrations of 50–200 µg/mL, but close monitoring of cell health is essential. Its application is often limited to short-term experiments or specific scenarios where bacterial resistance genes (e.g., in transfected cells) require selection pressure. However, it is more frequently employed in bacterial culture systems to maintain plasmid selection, especially in cloning workflows involving E. coli.
