It makes sense to me, Histidine is a basic amino acid,and has the right kind
of charge to some fit, may be not ideally, in the active site of trypsin.
I've seen a lot of unusual cleavages. It could also be due to the enzyme
prep being contaminated with chymotrypsin. But in this particular case, I
think that even a sequencing grade enzyme would cleave at the site if the
concentration of the enzyme is high enough or if the incubation is long
enough.
Amina
Amina S. Woods, Ph.D.
NIDA Intramural Program, NIH
5500 Nathan Schock Drive
Baltimore, MD 21224
Tel: 410-550-1507
Fax: 410-550-2971
e-mail: awoods@intra.nida.nih.gov <mailto:awoods@intra.nida.nih.gov>
-----Original Message-----
From: Association of Biomolecular Resource Facilities
[mailto:abrf-request@aecom.yu.edu]On Behalf Of VERNON SHOUP
Sent: Wednesday, March 14, 2001 2:38 PM
To: Recipients of ABRF List
Subject: Trypsin, unusual cleavage
Importance: Low
Hello, All
One of our proteins has an internal sequence of --TPHRRD--. After trypsin
treatment, I get mostly the expected cleavage between the two arginines.
But I also seem to get a significant amount of cleavage (~25%) between the
histidine and arginine. Does this make any sense to anyone?
Vernon
Vernon A. Shoup
Regeneron Pharmaceuticals
Rensselaer, NY
This archive was generated by hypermail 2b29 : Mon Apr 02 2001 - 10:20:49 EDT