induction with IPTG ? - (May/15/2006 )
I usually Induce my culture with IPTG and leave it for the whole time but here people have said that ." Induced with IPTG for 3,4, etc hours" . What do u mean by These "3 hours etc" .or i have to induce again with IPTG after 3 hours?????????.
it means to allow the culture to continue to grow in the presence of iptg for that length of time then spin it down and collect the supernate or pellet (or both).
you grow your culture to the required OD, and add the IPTG. The time when you add the IPTG is the "0", and by the way, 2h 3h etc... is the time you allowed your culture to row since the addition of iptg.
the "etc" means that you need to pick a length of time, not that you have to induce it multiple times
so, you can induce for a range of time, standard is typically 2 to 4 hours, but different proteins and purification schemes require altering this timeframe, especially if troubleshooting.