ProtSeq:Glu-C
David A. Schooley (schooley@unr.edu)
Thu, 15 Oct 1998 17:14:18 -0700
Another report of an anomalous cleavage:
A grad student recently cleaved an 8600 Da blocked peptide with
Glu-C, sequencing grade, freshly purchased from Boehringer. She used 0.1 M
Tris pH 8, which is not the phosphate recommended by Boehringer. We have
used Tris successfully in the past; it is our impression that there is
less absorption of protein to the tube at alkaline pH in Tris.
She observed cuts not only at E, but also at TWO different K
residues! Has anyone observed cutting at K with Glu-C? We are suspecting
either contamination of this lot of Glu-C with Lys-C, or a previously
unobserved cleavage due to the Tris buffer. I tend to discount the latter
as we cleaved a 37-amino acid peptide using these conditions previously
that contained two K's and had no cleavage at K.
Thanks in advance for any help!
David
David A. Schooley
Dept. of Biochemistry/330
Univ. of Nevada
Reno, NV 89557
schooley@med.unr.edu
tel: (702) 784-4136; fax (702) 784-1419