I just noticed that there was a typo on step 2 of the procedure for removal
of Mtt group.
It should be 5%TFA/DCM instead of 5%/DCM.
Anita Hong
AnaSpec, Inc.
2149 O'Toole Avenue, Suite F
San Jose, CA 95131
(408)452-5055 (phone)
(408)452-5059 (fax)
e-mail: service@anaspec.com
home-page: www.anaspec.com
***************************************************************************
AnaSpec was recognized as a "Leader of the Pack"
in custom peptide synthesis by The Scientist (October 27, 1997)
***************************************************************************
-----Original Message-----
From: anaspec <anaspec@best.com>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Cc: ABrf@aecom.yu.edu <ABrf@aecom.yu.edu>
Date: Monday, February 08, 1999 5:38 PM
Subject: Re: PepSyn: N-epsilon Lys derivatization
>Dear Jeni,
>
>My guess was you were using 2-chlorotrityl resin for you peptide synthesis.
>If you use HMP, Wang or Rink Amide resin, the Mtt group can be removed
>without cleaving the peptide from the resin by using the following
>procedure:
>1). Wash resin with DCM 2-3 times. This is very important because if
the
>resin is swollen in DMF the weak TFA solution will not removed the Mtt
>group.
>2). Wash resin with 5%/DCM(2X ten minutes) followed by 2.5%TFA/DCM(2X30
>minutes) until you do not see yellow solution which is an indication that
>the Mtt group is completely removed.
>
>Anita Hong
>AnaSpec, Inc.
>2149 O'Toole Avenue, Suite F
>San Jose, CA 95131
>(408)452-5055 (phone)
>(408)452-5059 (fax)
>e-mail: service@anaspec.com
>home-page: www.anaspec.com
>***************************************************************************
>AnaSpec was recognized as a "Leader of the Pack"
>in custom peptide synthesis by The Scientist (October 27, 1997)
>***************************************************************************
>-----Original Message-----
>From: jeni lauer <jlauer@ACC.FAU.EDU>
>To: Recipients of ABRF List <abrf@aecom.yu.edu>
>Date: Monday, February 08, 1999 10:46 AM
>Subject: PepSyn: N-epsilon Lys derivatization
>
>
>>Hello everyone,
>>
>>Before I begin with my latest question, I want to thank the people who
>responded
>>to my question regarding UPS systems. I'm still shopping, but I am much
>wiser
>>thanks to all of you!
>>
>>Our latest problem is with the derivatization of the epsilon-amino group
of
>Lys
>>(Fmoc chemistry). The first synthesis used Lys(Mtt) with HOAc/TFE/DCM
>>deprotection followed by the desired coupling. The problem was that the
>peptide
>>was purified in dismal yields due to almost complete cleavage from the
>resin
>>during the Mtt removal step (oops!). A solution phase coupling was
>attempted
>>with no success (boy am I glad to have been indoctrinated into peptide
>chemistry
>>in the post-solid phase era). Next we tried the incorporation of Lys(Dde)
>>instead of Lys(Mtt). Following hydrazine treatment, coupling, and cleavage
>the
>>peptide was all -~50 by MALDI-TOF. We decided this was due to hydrazine
>>destroying a Dnp group incorporated earlier in the peptide. The guess was
>also
>>helped along by the fact that our peptide was no longer yellow (oops!). We
>>looked at the early Dde papers and found no other means of removal besides
>>hydrazine. Our questions are...
>>1) Does anybody know of a way to remove a Dde group without harming the
>Dnp? (we
>>have more resin to work with)
>>2) If there is no knowledge of a Dnp-friendly removal, has anybody used
>Lys(Mtt)
>>with a specific resin whose linker IS stable to HOAc/TFE/DCM? We'd rather
>not
>>resynthesize again, but if there is no answer to #1, we'll be forced to.
>>We're also open to other ideas. I'd rather stick to tried and true
>protecting
>>groups because the new kids on the block don't always behave as their
>parents
>>would like us to believe (no offense meant toward any overprotective
>parents out
>>there).
>>
>>Thanks for all of your help. I'm sorry for the length of my message.
>>
>>Jeni
>>
>>Weather: The influx of family and friends from the north has begun. I
guess
>the
>>winter is starting to wear on those otherwise hearty folks. We're reminded
>again
>>of why we moved here. Reactions work just as well (or as poorly) in a
>tropical
>>climate as they did in MN. It's the golf game that is much improved here.
>>
>>
>>
>>Janelle Lauer
>>Department of Chemistry and Biochemistry
>>Florida Atlantic University
>>777 Glades Road
>>Boca Raton, FL 33431
>>Phone: 561-297-2094
>>FAX: 561-297-2759
>>
>>
>
>