From: "Haydn Ball" <hlb@prion.ucsf.edu>
Message-Id: <9701281541.ZM6275@prion.ucsf.edu>
Date: Tue, 28 Jan 1997 15:41:43 -0800
Subject: Asp dehydration
To: Recipients of ABRF List <abrf@aecom.yu.edu>
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