Aminopeptidase M - Are GAGs a problem

[B Lauder]

I'm wanting to isolate some GAGs by digestion of the protein to which 
they are attached (perhaps by papain) and then use a further enzyme to 
cleave the final few amino acids which remain attached to the GAG (I 
want the linkage region intact, with the amino acid to which the GAG is 
linked present). I guessed that aminopeptidase would be the thing to go 
for. However, I have no experience of this procedure and wonder if the 
enzyme will stop cleaving the N-terminal amino acid when it reaches 
the GAG chain ? If it does will a carboxypeptidase do the job okay 
from the other end?

I'd be grateful for any comments on enzyme choice or on the 
potential problems. 

Thanks
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Bob Lauder
Biological Sciences,
University of Lancaster, UK   
Home page  - http://bssv01.lancs.ac.uk/gig/ppl/bob/home.htm