G418 Disulfate

108321-42-2

C20H40N4O10 · 2H2SO4

692.71

White or off-white powder

Water: 100 mg/mL (clear and complete)

Source: Micromonospora rhodorangea
Water Content (Karl Fischer): ≤12.0%

≤ 30 °C

Spectrum: G418 Disulfate is toxic to susceptible bacteria, fungi, yeast, protozoa, helminths, mammalian cells, and plants.

Microbiology Applications: G418 Disulfate is used as a gene selection agent during transfection of eukaryotic cells.

Eukaryotic Cell Culture Applications: G418 Disulfate is routinely used as a selection agent in cell culture after transfection of eukaryotic cells. Resistant cells express the neo gene which produces aminoglycoside 3'-phosphotransferase (APT 3' I or APT 3' II), a protein that confers resistance to G418 Disulfate and other aminoglycoside antibiotics.
Optimal working concentrations:

Mammalian cell lines: 200 mg/L – 1000 mg/L
Bacteria and algae: ≤5 mg/L

The optimal working concentration of G418 Disulfate to select for resistant clones depends on the cell line, reagent quality, reagent lot, media, growth conditions, cell density, cell metabolic rate, cell cycle phase, and plasmid quality. A kill curve should be performed to determine the optimal concentration for each experimental system.
Use the following guide to determine the appropriate concentration:

5 mg/L - 1400 mg/L (mammalian cells)
0.1 mg/L - 50 mg/L (bacteria and algae)

A working concentration of 200 mg/L is usually sufficient after resistant mammalian clones are selected and can be used for maintenance until stable resistant clones are selected.
The Selectivity Factor is a quantifiable measure of how efficient an antibiotic is during the process of gene selection. TOKU-E scientists tested the selectivity factor of G418 for BHK-21 cells and HeLa cells. They found that G418 is an ideal selection antibiotic for transfected BHK-21 cells but not optimal for HeLa cells. The method uses a modified MTT assay, which can be used to numerically determine the antibiotic efficiency (Delrue et al, 2018). .
For information on relevant cell lines, culture medium, and working concentrations, please visit the Cell-Culture Database.