attached mail follows:
Georgina -
The proper approach depends on the sequence of your peptide.
1) If your peptide is aggregating via hydrogen bonding, then try
reversed-phase at neutral pH with 100 mM NaClO4 in the mobile phases. See
Guo et al., J. Chromatogr. 359 (1986), pg. 507, Fig. 2.
2) If it has basic residues in one part of the sequence and acidic
residues in the other part, then it could be aggregating through
electrostatic attraction. In that case, purify it via cation-exchange with a
salt gradient in 20% acetonitrile at pH 3. See Alpert and Andrews, J.
Chromatogr. 443 (1988) 85. [NOTE: Since this is a cyclic peptide, I presume
the N-terminus is amide-bonded to the C-terminus. In that case,
cation-exchange will work only if you have at least 1 basic residue].
3) If aggregation occurs through hydrophobic interaction, then try
Hydrophilic Interaction Chromatography (HILIC), with a decreasing organic
gradient. See Alpert, J. Chromatogr. 499 (1990) 177.
If you have any more specific questions, please tell us your sequence.
Regards,
Andy Alpert
PolyLC Inc.
9151 Rumsey Road, ste. 180
Columbia, MD 21045 USA
tel: (410) 992-5400 FAX: (410) 730-8340
****************************************************
<< Subj: agregation
Date: 09/14/2000 8:08:30 PM Eastern Daylight Time
From: tonareli@fbcb.unl.edu.ar
Sender: abrf-request@aecom.yu.edu (Association of Biomolecular Resource
Facilities)
To: abrf@aecom.yu.edu (Recipients of ABRF List)
I have an aggregation problem with a synthetic cyclic peptide of 15
aa. We want to purifie up to 95% by reverse phase-preparative
HPLC. Could someone help me?
Thank you in advance.
Dra.Georgina Tonarelli
Facultad de Bioquimica y Cs. Biologicas
UNL.- Argentina
e-mail: tonareli@fbcb.unl.edu.ar
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