Preparing chemically competent cells

• Grow a 5-25mL culture to an OD₆₀₀ of 0.2 [math]\displaystyle{ \rightarrow }[/math] 0.5
• Centrifuge for 10 minutes at 3000rpm and [math]\displaystyle{ 4^o }[/math]C.
• Remove supernatant and replace with 10% original volume TSS.
• Make 100uL aliquots and store at [math]\displaystyle{ -80^o }[/math]C.

TSS (50 mL)

• 5g PEG 8000
• 1.5 mL 1M MgCl2
• 2.5 mL DMSO
• LB to 50 mL