Specificity of Endoproteinase Asp-N

[Marcus, Dr J.]

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