Specificity of Endoprot

[Marcus, Dr J.]

Dear netters:

In an earlier post I suggested using Iodoacetamide to 
modify Cys residues to make them susceptible to Trypsin 
cleavage.  I was quite mistaken, as Daniel Milligan kindly pointed out 
to me.  Shaun Black's suggestion to use the ethyleneimine is the 
suggestion that I should have made.  Sorry if I caused any 
confusion.  

Regards,
John

> 
> --------------------------------------
> Date: 11/11/96 4:13 PM
> To: protein-analysis at net.bio.net
> From: Marcus at tpp.uq.edu.au
> Dear Kali,
> 
> You wrote:
> 
> > I am looking for something to specifically cleave at Cys residues.  I 
> > am aware of Endoproteinase Asp-N which cleaves at Aspartic acid also. 
> > Does anyone know of anything I could use? I am looking forward to your 
> > great ideas.
> > Thanks for the help, Kali
> > 
> If you are really desparate you might try modifying Cys 
> residues with iodoacetamide.  Once modified, I think it 
> allows trypsin to cleave at that position (maybe not 
> efficiently but you should get some cleavage).  You would 
> have to modify both arginines and lysines (see Pierce 
> catalog) so that they are not susceptible to trypsin 
> cleavage.  A bit of work, but if you are desparate, it 
> might work.
> 
> Hope that helps.
> 
> John
> 




_________________________________________________________
John Marcus            Marcus at tpp.uq.edu.au (Dr J.Marcus)
Cooperative Research Centre for Tropical Plant Pathology
5th Level John Hines Building
University of Queensland
St. Lucia, QLD 4072
AUSTRALIA

Fax: 61-7-3365-4771
Phone: 61-7-3365-4764