[Protein-analysis] protease

[Abla Sipanis]

Hi all,

I'm looking for a protease that has a very specific cleavage site, and 
quite long so that it wouldn't cut at all in the whole Arabidopsis 
proteome. Do you think that this does exist ?
Amersham for example claims that the recognition site for Prescission is 
LeuGluValLeuPheGln/GlyPro. Does it mean that this is really the only 
sequence that will be cut ? And by the way, I would like to express this 
protease in vivo, so that I would need a cDNA. Perhaps difficult for a 
patented enzyme ?

Any suggestion would be ighly appreciated.
Thanks for you help !

Abla