Re: your mail
peptide technologies corp. (peptech@access.digex.net)
Thu, 16 Apr 1998 10:25:28 -0400 (EDT)
A method that was followed for di DNP angiotensin I was to dissolve 100 mg
in DMF and 0.1 N NaHCO3 (6.5 ml DMF, 1 ml Base or approc 70% DMF) adjust
pH to 8 and treat with 25 X M His, mercaptoethanol (0.65 ml) after 3 hr or
by monitoring by HPLC reaction complete, acidify with HOAc to pH3 then
dilute with water and extract with ethyl acetate.
The best way to remove the DNP group is before cleavage from the resin,
wash the peptide resin a few times with DMF then react with 25 X moles His
of thiophenol in DMF for at least 15 min to an hr (can follow end of
reaction by monitoring supernatant by taking an aliquot and diluting in
ethanol and reading abs. at 350). Follow with washes in DMF then a few
washes in ethanol then you can work up for cleavage.
Ref. early one for this method is JM Stewart, M Knight,ACM and T Paiva,
Progress in Peptide Research II, ed. S. Lande, 1972, Gordon and Breach NY
p. 59-64.
ref. for use of b-ME is HJ Goren and M. Fridkin,Int. J. Peptide Prot.Res.
11 1978, pp. 1-8
Hope this is helpful
Martha Knight
President
Peptide Technologies Corporation
phone 301 869-7306 Fax 301 869-7308
On Wed, 15 Apr 1998, Mary Bower wrote:
> Date: Wed, 15 Apr 1998 14:01:30 -0500
> From: Mary Bower <bower@biochem.purdue.edu>
> To: Recipients of ABRF List <abrf@aecom.yu.edu>
>
> I am wondering whether anyone out there has had any success in removing the
> (His) DNP group from a cleaved peptide?? The N-terminal Boc protecting
> group has also been removed. The ABI peptide cleavage booklet mentions a
> B-mercaptoethanol procedure but doesn't go into details.
>
> Thanks in advance.
>
> Mary Bower
>
> Mary Bower
> Instrument Specialist
> Purdue University
> Department of Biochemistry
> West Lafayette, IN 47907
>
> Phone (765)494-6540
> Fax (765)494-7897
> email; Bower@Biochem.purdue.edu
>
>
>