IPTG induction - at what cell density (May/05/2008 )
Do you add inducer to cell culture at A600=0.5 or 0.8?
I would start at 0.5, unless the protein is toxic to the cells, then I'd induce at a higher OD for a shorter time.
You can use 0.8 OD cell density with 0.5mM to 4mM concentration of IPTG. Prepare IPTG priar to use and sterile filter it.
I did it as high as 1.0 at OD=600nm without trouble and with 1mM IPTG
we use 0.5 or 1 mM final concentration of IPTG at OD600=0.6. i think this is the best. its up to you.
I often induce the culture at OD600=0.5. But I tried induction at OD600=1.0 without any problem