G418 Disulfate Solution (50 mg/ml in water)

- Overview
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    Background
    
    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.
- Properties
  - CAS Number
    
    108321-42-2
    
    Molecular Formula
    
    C20H40N4O10 · 2H2SO4
    
    Molecular Weight
    
    692.71 g/mol
    
    Appearance
    
    Clear and colorless solution
    
    Other Properties
    
    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
    
    Storage
    
    2-8°C
    
    * For research use only
- Applications
  - Application Description
    
    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.