How can I determine the IPTG concentration for difference strains of E.coli
For example, I found in a research paper for protein expression
1. protein in expression vector (T5 promoter) in E.coli JM103 >> using 1mM IPTG
2. same protein in no.1 and asme vector in E.coli m15 >> using 0.15 mM IPTG
I doubt how to determine a IPTG concentration even though the same protein gene and same vector
Please suggest me
Thank you for your all response
A broad range of IPTG (0.05-2 mM) might work for your construct in various strains and various media. I wouldn't bother too much with optimizing that if you get the protein you need.
If you want to know the optimal IPTG concentration you need to determine that experimentally for each construct/strain/media/condition.
The only way to find the concentration that suits your protein the best is by testing.
Start with 0,1mM, 0,5mM and 1mM at 30°C, 180rpm for 4h in LB oder dYT media. This should give you a first impression on how your protein behaves for purification.
Hi Sarit,
There are lots of things that can affect the yield of soluble protein that you get.
I find the best way is to check this experimentally, try using a range of concentrations of IPTG at different temperatures (maybe 20C, 30C and 37C), and ideally a couple of different strains. Then check total, soluble and insoluble protein fractions - this should give you a pretty good handle on the conditions that would suite you best. it shouldn't be too much work to work out the optimum conditions for your protein of interest.
Best of luck.
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