PepSyn: Difficult Sequence

procor@smtpgate.bcsew.edu
Mon, 09 Feb 98 12:09:54 -0600

Hello ABRFers,

I am having a problem synthesizing a peptide with the sequence
PITKYIMTCMSADLEVVT. I am using std FMOC chemsitry with OPfp esters,
20% Pip as the deblock, DMA as the solvent and PEG-PS as the starting
resin. I am using a 9050 instrument. I dried the resin and cleaved in
92.5 % TFA, 2.5% TIS, 2.5% ethanethiol for 2 hrs. I precipitated the
peptide in fresh ether and washed it 3x. The pellet was dried on a
lyophilizer. The resulting pellet was very granular. I tested the
crude peptide using RPHPLC, 5-60% ACN and saw no clear peak. I sent
the crude out for ES MS analysis and the tracing showed alot of noise
but no target peptide. I know this sequence is very hydrophobic and I
may have to change my purification strategy but I don't feel like I
even have the peptide on the resin yet. Any sugesstions would be
appreciated.

Thanks,

Trudy Holyst
Blood Research Institute
The Blood Center
Milwaukee WI 53201

procor@smtpgate.bcsew.edu