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