Given no info on the protein, it can be anything.
Is it recombinant? Which host? etc.
Oxydation (cys, met) is also a possibility
By the way, deamination concerns asn and gln, not lys.
Best,
Nadir
Pr. Nadir T. Mrabet
Structural& Molecular Biochemistry
Nutrigenex - INSERM U-954
Nancy University, School of Medicine
9, Avenue de la Foret de Haye, BP 184
54505 Vandoeuvre-les-Nancy Cedex
France
Phone: +33 (0)3.83.68.32.73
Fax: +33 (0)3.83.68.32.79
E-mail: Nadir.Mrabet<at> medecine.uhp-nancy.fr
On 18/02/2011 19:45, Soisson, Stephen M wrote:
Possibly deamidation of the protein, in particluar one or more
lysines. What does the Mass spec look like?
Cheers,
Steve
------------------------------------------------------------------------
*From:* CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] *On Behalf
Of *Ulli Hain
*Sent:* Friday, February 18, 2011 12:14 PM
*To:* CCP4BB@JISCMAIL.AC.UK
*Subject:* [ccp4bb] off-topic: 2 peaks on Cation
Hi, I was wondering if anyone had possible explanations for a
recombinantly expressed soluble protein that runs as 2 equal, slightly
overlapping peaks on a cation exhanger but as one peak on a size
exclusion column and same electrophoretic mobility on SDS-PAGE.
-Ulli
Adelaide Ulricke Hain
PhD Candidate
Johns Hopkins Bloomberg School of Public Health
Department of Biochemistry and Molecular Biology
615 North Wolfe Street
Baltimore, MD 21205
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