>I have a peptide that has Gln at its C-terminus that I am trying to
Danny-
First, presumably you mean N-terminus, as a C-terminal Gln
cannot cyclize. The mechanism for this reaction is the
intramolecular nucleophilic attach of the lone pair of nitrogens on
the alpha-amino group on the amide side chain carbonyl group.
Therefore, the reaction is expected to be HINDERED when the amino
group is protonated at acidic pH. What you want are basic conditions
to ensure that the lone pair is non-protonated.
I would suggest a good organic base like triethylamine.
David
David A. Schooley
Dept. of Biochemistry/330
Univ. of Nevada
Reno, NV 89557
schooley@unr.edu
tel: (775) 784-4136; fax (775) 784-1419
NOTE NEW AREA CODE: Mandatory after 5/15/99
This archive was generated by hypermail 2b29 : Wed Jan 12 2000 - 16:13:53 EST