James Ferguson
CTL Immunotherapies
MiniMed Technologies
12744 San Fernando Road
Sylmar, California 91342, USA
(818) 362-5958 x3091
(800) 999-9859 x3091 toll free
(818) 364-2246 FAX
> ----------
> From: peptide core facility
> Sent: Wednesday, March 3, 1999 11:22 AM
> To: Recipients of ABRF List
> Subject: Prevent of Oxidizingof Met.
>
>
>
> Dear ABRFers,
>
> I have a problem with synthesing the 33mer with 2 Met and 1 Trp in it.
> After synthesize the peptide and cleavage with B mixture of cocktail, I
> found the Ms +32 and HPLC the rt is earlier too, compared to the earlier
> same peptide.
>
> I made this peptide few times the same sequences, I don't know where it
> went wrong. So, changed the fresh Met, and other all the scavanger, and
> ether too.
> But, the results are the same.
>
> We have the ABI431A synthesizer, and using Fast-Fmoc Chemistry, but I
> changed the B module Step 17-Fxn#98 6 to 30 , it means the time of the
> deprotecting is longer and F Module Step22-Fxn#98 30 to 60. But I have
> been
> using this changed program for few years, it was OK, until last few month
> I
> am having a trouble.
>
> So, I could not figure it out what went wrong. If anybody have some idea
> what is the reason, please help me to prevent the happening again of the
> oxidizing Met.
>
> Thanks in the advance,
>
> Sook Shin
> Peptide Core Facility
> Queen's University
> Dept. of Biochemistry
> E-mail; hss@post.queensu.ca
> Tel;613-533-6837
> Fax;613-533-2497
>
>