scrap cells from plate and add to the carrier DNA.
Add in the following order:
1-2 μl DNA-plasmid (up to 30-50 μl)
240 μl PEG (50%)
36 μl Li-Ac (1M)
resuspend with blue tip
incubate at 30°C or RT at least 30 min
heat shock: 45°C, 15 min (or 42°C for 20 min)
spin down, resuspend in 100μl H2O and plate everything on corresponding medium
Material:
Plasmid: 100 ng - 1 μg
carrier DNA: salmon/herring sperm DNA in H2O, 2mg/ml stock, 500 μl aliquots, heat-inactivated at 95°C for 5-6 min and put on ice before use (has to be done once).