• G418 disulfate 50mg/ml packaged and labeled.

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SKU: G020-G021

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G418 Disulfate Solution (50 mg/ml in Water) is an aqueous solution of G418 Disulfate.  G418 Disulfate, an aminoglycoside antibiotic originally isolated from Micromonospora rhodorangea,  is routinely used for gene selection in cell culture.  The aqueous format allows for streamlined workflows.

We also offer:

  • G418 Disulfate (G001)
  • G418 Disulfate, EvoPure (G030)

    CAS Number


    Molecular Formula

    C20H40N4O10 · 2H2SO4

    Molecular Weight

    692.71 g/mol

    Mechanism of Action

    G418 Disulfate, along with other aminoglycosides, prevent protein synthesis.  Resistance to G418 Disulfate is conferred by the neomycin resistance gene (neo) from either Tn5 or Tn601 (903) transposons. Cells successfully transfected with resistance plasmids containing the neo resistance gene can express aminoglycoside 3'-phosphotransferase (APT 3' I or APT 3' II) which covalently modifies G418 to 3-phosphoric G418,  which has negligible potency and has low-affinity for prokaryotic and eukaryotic ribosomes.

    Storage Conditions


    Tariff Code



    G418 disulfate is toxic to susceptible prokaryotic and eukaryotic cells including fungi (yeasts and molds), bacteria, mammalian and plant 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 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 about the Selectivity Factor, click here.

    For more information on relevant cell lines, culture medium, and working concentrations, please visit the TOKU-E Cell-culture Database.

    Microbiology Applications

    G418 disulfate can be used as a selection agent for G418 resistant bacteria or fungi after transformation.





    Clear and colorless solution


    Micromonospora rhodorangea

    Biological Assay

    ED50 Resistant: Not less than 2,500µg/mL
    ED50 Sensitive: Not more than 400µg/mL

    Elemental Analysis

    Carbon: 28.80 - 36.07%
    Hydrogen: 5.76 - 7.76%
    Nitrogen: 6.72 - 8.41%
    Waters of Hydration: 0 to 6


    Not more than 1.0%

    Water Content (Karl Fischer)

    (Powder) Not more than 12.0%

    Potency (on a dry basis)

    Not less than 720µg/mg


    280nm (1mg/mL): Not more than 0.015
    570nm (100mg/mL): Not more than 0.10


    4.6 - 6.0

    Optical Rotation

    +104° to +121°





    References for G418 Disulfate from TOKU-E:

    Delrue I, Pan Q, Baczmanska AK, Callens BW and Verdoodt LLM (2018)   Determination of the selection capacity of antibiotics for gene selection.   Biotechnol. J. 13(8):1700747  PMID 29436782

    Foltyn M et al (2019)  The physiological mTOR complex 1 inhibitor DDIT4 mediates therapy resistance in glioblastoma. B. J. Cancer 120:481-487

    Suasnavas EA (2013)  Characterization and potential utility of porcine trophoblast-derived stem-like cells. MS thesis, Utah State University, Logan, UT


    Aragão FJL and Brasileiro ACM (2002)  Positive, negative and marker-free strategies for transgenic plant selection. Braz. J. Plant Physiol. 14(1):1-10

    Davis, BD (1987)  Mechanism of bactericidal action of aminoglycosides.  Microbiol. Rev. 51(3):341-50

    Lin-Cereghino, J et al (2008)  Direct selection of Pichia pastoris expression strains using new G418 resistance vectors.  Yeast 25:293-99. 

    Shin, Y (2007)  Selection of NptII transgenic sweet potato plants Using G418 and paromomycin.  J. Plant Biol. 50(2):206-12

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