what are Saponins used for?

[Kamin Johnson]

In article <3ca0cu$j5h at decaxp.harvard.edu>, mlevin at husc7.harvard.edu
(Michael Levin) wrote:

>    I just saw a recipe for some kind of immunohistochemistry where
> they suggest using Saponin instead of Tween-20 in the washes -
> something about it being a better soap-like-thing that Tween. Does
> anyone know the scoop on this - what is the difference, and why
> do people use it insteadof Tween? Please reply to
> mlevin at husc7.harvard.edu. Thanks.
> 
> Mike Levin

Saponin has been used as a selective membrane permeabilizing agent.  In
the literature, saponin is thought to permeabilize the plasma membrane
while leaving membranes such as the ER, etc intact.  I believe this has
something to do with cholosterol content of the membrane.  

kam