Date: Wed, 29 Jan 1997 14:04:20 +0000 (GMT)
From: KNIERMAN MICHAEL D <KNIERMAN_MICHAEL_D@Lilly.Com>
Subject: RE: Asp dehydration
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Haydn,
Do you have evidence that the dehydration is at the asp resudue? It
could also be a dehydroalanine from a ser residue.
Michael D. Knierman
Eli Lilly
knierman@lilly.com
Disclaimer: Any opinions stated above are my opinion and do not reflect any
position of Eli Lilly and Co.
<Hello ABRFers
<
<We have recently synthesized the following sequence using Fastmoc
chemistry on
<an ABI433A - ESQAYYDGRRSS. Our problem is that the final product contains
a
<very high proportion (~45%) of the dehydrated Asp impurity. We are using
EDT,
<thioanisole, water and TFA (1:2:2:35) for cleaving the peptide from the
resin.
<Any suggestions as to how we can minimize this problem, which seems to be
<sequence related since other Asp-containing peptides we have made do not
<contain the impurity, would be greatly appreciated.
<
<Many thanks
<
<Haydn Ball, PhD
<Dept of Neurology,
<UCSF
<San Francisco
<CA 94143-0518
<
<hlb@prion.ucsf.edu
<Tel (415) 476 6485