Suryaprakash: you could use TFA, better yet try and see if the peptide is
soluble in acetic acid, try upto 20 %. Acetic acid will give you a huge
peak with the void volume. The question is does your peptide bind to C-18
under the ususal conditions of operation (ie H2O/TFA/MeCN). It surprises
me too that you an insoluble hygroscopic peptide. How was it made and what
might the crude material contain. Under some conditions of deblocking,
there are enough scavengers/other stuff present that yields a gelatinous
mess. My other suggestion would be to relyophilize this peptide from
aqueous acetic acid or TFA and observe the results, I expect that you have
already tried out a few of these. Is your peptide soluble in buffer such
as tris or dilute ammonium hydroxide? this could give you a partailly pure
peptide by binding to a C-18 cartridge , then eluting in neat acetonitrile
or methanol. good luck, gautam
Gautam Sarath
N-226, Beadle Center
Protein Core Facility - Center for Biotechnology &
Department of Biochemistry
University of Nebraska-Lincoln
Lincoln, NE 68588-0664
Phone: 402-472-2928
FAX: 402-472-7842
http://www.biotech.unl.edu/Proteins/index.html