IPTG induction

[aftabac]

Hi
for the induction of expression of our gene of interest that is based on lac promoter we usually use IPTG instead of lactose, can anyone of you would like to explain it why we preferably use IPTG instead of Lactose.

regards
aftab

[kmunson779]

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Unlike allolactose, the sulfur (S) atom creates a chemical bond which is non-hydrolyzable by the cell, preventing the cell from "eating up" or degrading the inductant.

[mani14s]

IPTG is toxic to cells & also costly. so its better to go for lactose

[aftabac]

yes, IPTG is toxic to cell but its only toxic when its concentration is high. but the important thing is that it is not hyrolyzed by the cells, so it stayes inside the cells and give a constant induction and expression of the gene and hence protein, but as compared to it if lactose is used it is metabolized and so no more lactose is there in the cells that could induce the expression of gene.
regards
aftab

[one.tjc]

Sorry to drag up an old thread, but when IPTG (0.1M) is added to a fermentation culture, what effects does it have on the growth rate of the cells.

I'm assuming that the cells will stop dividing and instead churn out protein, so the A600 will level off as this occurs?

Cheers!

[kezia]

hey...
IPTG has a sulfur molecule in it. so it cannot be metabolized by bacteria...and hence can be used to induce the specific gene of interest...
Lactose , on the other hand, is readily metabolized by bacteria and cannot be left for the induction... and more over lactose gets oxidized to lactic acid which may inhibit the bacterial growth...
i hope i ansered ur Q...