Thanks everyone. We have seen this on some His-tagged proteins, and
also on some w/o the tag. It also occurs on both acidic and basic
proteins. Apologies for not mentioning the fact that it appears to be
associated with Cys by MS-MS data (again, not CM!). In some cases the
intact proteins appear to modified 95% or greater...(+58 per Cys).
Scott
______________________________ Reply Separator _________________________________
Subject: RE: +58amu?
Author: Beverly DaGue <Beverly.B.DaGue@vanderbilt.edu> at SMTP
Date: 8/8/00 7:32 AM
Hi, Scott,
Are these recombinant proteins of the His-tag type and could the
contaminant be Nickel (avg atomic weight 58.6934 amu, monoisotopic mass
57.935 amu) from the column used to isolate the proteins? Or am I way out
in left field?
B. DaGue
Sr. Research Assistant
Mass Spectrometry Research Center
Vanderbilt University Medical Center
Nashville, TN 37232
615-343-8430
-----Original Message-----
From: Scott Chamberlain [SMTP:Scott_Chamberlain@cc.chiron.com]
Sent: Monday, August 07, 2000 3:32 PM
To: Recipients of ABRF List
Subject: +58amu?
Hi folks,
We've seen a +58 species several times when dealing with recombinant
proteins (not carboxymethylated!). Does anyone have any ideas as to
what this could be?
Thanks in advance...
Scott Chamberlain
Protein Structure Analysis
Chiron Corp.
510-923-2839
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