I am a fish - 29-10-2005 at 02:40
Papain (a protease enzyme) is available from many supermarkets and food suppliers, as the active ingredient of most meat tenderizers. Unfortunately,
it is usually diluted with salt and starch.
How can I isolate pure papain, without denaturing it?
Eclectic - 29-10-2005 at 10:14
Dialysis
http://sciencekit.com/category.asp?c=436410&sid=froogle
Maybe use some amylase to digest the starch.
[Edited on 29-10-2005 by Eclectic]
Ramiel - 30-10-2005 at 02:55
According to my Molecular Biology laboratory manual, detergents solubilize proteins without denaturing them. Something like 10% solution in water
(e.g. sodium dodecyl sulphate). I don't know about the, er... veracity of this claim though.
If it is true, a simple centrifugion and chemical treatment ought to get you a nice pallet of protein.
chemoleo - 30-10-2005 at 17:53
Yes, SDS and other detergents solubilise the protein, but often at the price of denaturing it. It depends on the protein essentially.
Otherwise - the papain should be soluble, while starch isnt. Filtering should be the first thing to try. Then, dialyse it. However, beware of the fact
that proteins in low or no-salt buffers (low ionic strength) are unstable and often denature/unfold/aggregate. Thats probably a reason why salt is
added.