Specificity of Endoprot

Marcus, Dr J. J.Marcus at botany.uq.edu.au
Mon Nov 11 23:30:41 EST 1996

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 


> --------------------------------------
> 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

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

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