Gene fusion and site specific cleavage

[kaya at mscf.med.upenn.edu]

Does anyone know of a chemical or enzymatic method for cleaving a peptide bond 
at e N-terminus of a specific amino acid sequence?  I 

I know that Factor XIIa cleaves before the sequence 

		-Ile Val Gly Gly Thr Val,

but are there any others?

Thanks inadvance for your help,

angie

KAYA at MSCF.UPENN.EDU