TSS buffer is used to make chemically competent cells.
To make 50 mL:
- 5g PEG 8000
- 1.5 mL 1M MgCl2 (or 0.30g MgCl2*6H20)
- 2.5 mL DMSO
- Add LB to 50 mL
Filter sterilize (0.22 μm filter)
- Note 1: pH from original Chung CT paper calls for pH to be acidic (pH=6.5)... be sure to pH solution before sterilization
- Note 2: If using non-chemically resistant filters (e.g., cellulose nitrate), add DMSO after sterilization. DMSO should be sterile in and of itself, so it may be prudent it add it afterwards if you are unsure about the compatibility of your filters.
Store at 4˚C or -20˚C.