Date: Thu, 16 Jan 1997 12:17:22 -0500 (EST)
From: "peptide technologies corp." <peptech@access.digex.net>
Subject: Re: pepsyn
In-Reply-To: <v02140b02af0155e95f8e@[134.197.50.216]>
To: Recipients of ABRF List <abrf@aecom.yu.edu>
David,
George is right. Boc PCA and CBZ PCA have been commercially available
from Peninsula and Bachem among others. The reason is solubility.
Martha Knight
Peptide Technologies
On Tue, 14 Jan 1997, David A. Schooley wrote:
> Date: Tue, 14 Jan 1997 23:28:54 GMT
> From: "David A. Schooley" <schooley@unr.edu>
> To: Recipients of ABRF List <abrf@aecom.yu.edu>
> Subject: Re: pepsyn
>
> Pat-
> True pyroglutamic acid (such as Aldrich P7,520-2,
> (S)-2-pyrrolidinone-5-carboxylic acid, CANNOT be converted to a Z, T-Boc,
> or FMOC derivative, as it has no amino group- that becomes an amide on
> conversion to pGlu. Sounds like you may have started with Z-glutamic
> acid?? What you may be seeing is some of the peptide with N-terminal Glu,
> some with N-terminal pyroGlu (same as N-terminal Glu -water in molecular
> weight), and some that is still protected???? Or did you start with
> Z-glutamine? The latter will spontaneously form pyroGlu under basic
> conditions, Z-Glu will not..
>
> >We are doing small molecule organic synthesis in our cominatorial
> >lab. We recently made some compounds which involve amide bond
> >formation using N-Z-Pyroglutamate as an acid monomer coupled with
> >various amines. Analytical HPLC of these samples exhibit high purity
> >(generally >90%). However, after having run these samples on HPLC, I
> >did ESI-MS on them the following day and some of them have 6, 8, 10
> >major ions that show up. My question is this. Is it possible that
>
> David
>
> David A. Schooley
> Dept. of Biochemistry/330
> Univ. of Nevada
> Reno, NV 89557
> schooley@med.unr.edu
> tel: (702) 784-4136; fax (702) 784-1419
>
>
>