G418 Disulfate Solution (50 mg/ml in water)

108321-42-2

C20H40N4O10 · 2H2SO4

692.71 g/mol

Clear and colorless solution

Source: Micromonospora rhodorangea
Water Content (Karl Fischer): (Powder) Not more than 12.0%
PH: 4.6 - 6.0
Absorbance: 280nm (1mg/mL): Not more than 0.015 570nm (100mg/mL): Not more than 0.10
Optical Rotation: +104° to +121°
Concentration: 50mg/mL
Identification: IR, HPLC - Passes test

2-8°C

Spectrum: G418 Disulfate is toxic to susceptible prokaryotic and eukaryotic cells including fungi (yeasts and molds), bacteria, mammalian and plant cells.

Microbiology Applications: G418 Disulfate can be used as a selection agent for G418 resistant bacteria or fungi after transformation.

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 sulfate 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 concentration to use to generate a kill curve:

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. Authors 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 I et al, 2018). .
For more information on relevant cell lines, culture medium, and working concentrations, please visit the TOKU-E Cell-culture Database.