digitonin in nuclei isolation buffer - why?
donald at ljcrf.edu
Wed Jan 12 19:33:49 EST 1994
Melissa Melan wrote:
> The digitonin is most likely included in the isolation buffers as a
>disrupting agent that affects plasma membranes and not nuclear, mitochondrial orchloroplast
>membranes. Digitonin acts by dissrupting the association of
>cholesterol and phospholipids making "holes" in the membranes. Nuclear
>envelope membranes have a much lower cholesterol content than plasma membranes
>and thus are less affected by digitonin or other saponins. I wouldn't bet
>my life though that its completely harmless to the nuclei.
>Hope that this helps.
That's right. I might add that digitonin is routinely being used now to permeabilize cells for assaying
import of nuclear proteins (Adam, S. A., Marr, R. S., and Gerace, L. (1990). Nuclear protein import in
permeabilized mammalian cells requires soluble cytoplasmic factors. J. Cell Biol. 111: 807-816.) The
method relies on the fact that digitonin at appropriate concentrations does not solubilize the nuclear
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