PepSyn: double AA insertion?

Luisa Rusconi (Luisa.Rusconi@eu.pnu.com)
Fri, 10 Dec 1999 10:24:33 +0100

Dear ABRFers,

one colleague asked me to characterize a peptide mixture she obtained
from the synthesis of a biotinylated, 20 AA-long phosphopeptideamide
assembled by Fmoc/tBu chemistry: the quality of the crude was very
poor, although she used standard reliable methods. Now following
analysis by trypsin/V8 mapping, N-terminal sequencing and ES-MS, one
thing that seems to have happened during the synthesis is double
insertion of the C-terminal Asp residue. One possible reason would be
Fmoc-release caused by the aminic resin, but does any of you have
experience or references on this kind of side reaction?

Thanks to all in advance,

Luisa


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Luisa Rusconi
Biochemistry
Dept. of Biology
Pharmacia & Upjohn
20014 Nerviano (MI)
Italy