I need IPTG to induce big volumes of E.coli cultures to do protein purification. Many suppliers advertise their IPTG as being "dioxane-free". What difference does it make ?
My guess is that dioxane is a residue that can be left over in variable amounts from the preparation of IPTG, and that dioxane is toxic to the bacteria. Since the amount is variable, the growth of the bacteria and induction by IPTG can be variable also. By eliminating dioxane from the IPTG, this source of variability is removed.
I agree with Adam; toxicity may be a problem for some applications. However, we have been using 1 mM IPTG without any specific "dioxane-free" label with no trouble for inducing lac-inducible genes in E. coli.
Dear Martin Chenal ,
As said by Adam B Shapiro and Pierre Béguin the presence of dioxane could potentially interfere with normal cellular function (under very specific circumstances). Dioxane is considered as a toxic substance. Therefor it might be relevant to use dioxane free IPTG.
Dioxane is used (or used to be used) in all sorts of applications and one of them is as solvent. Historically the last synthesis step of IPTG is crystallization from dioxane, see:
Carlsson, U., Ferskgárd, P. O., & Svensson, S. C. (1991). A simple and efficient synthesis of the inducer IPTG made for inexpensive heterologous protein production using the lac-promoter. Protein Engineering, Design and Selection, 4(8), 1019-1020.
https://academic.oup.com/peds/article-abstract/4/8/1019/1438890
Probably because of this manufactures mention this (and I personally suspect that they use it as a marketing tool to pursue you to buy the more expensive version of IPTG).
Best regards.
Rob Keller , actually, there is a paper (doi:10.1006/prep.1996.0106) whose authors claim that dioxane-free IPTG works better. Still, until better data appears, I agree thta the dioxane-free label is most likely a marketing gimmick.
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