Re: Digestion of Toxin
Katheryn Resing (Katheryn.Resing@Colorado.EDU)
Wed, 3 Mar 1999 13:32:50 +0000
Your protein is probably also small, am I correct? You probably won't get
it to digest with trypsin. If its fairly acidic, you might have luck with
V8. If you digest it with CNBr, you will probably get large peptides that
may hang together because of all the disulfides. You can get some idea of
whether this will happen by looking at the distribution of cys in the
peptides you expect to be produced.
Why do you want to digest it in the disulfide bonded form? Usually people
want to do this to identify the disulfides. If you do that at neutral pH,
there is a danger that you will get "shuffling" of the disulfides. Thus
for that purpose, one normally digests with pepsin under acid conditions.
Even fairly tightly "knotted" proteins will usually digest with pepsin.
Katheryn Resing