re: mannosylation of peptides

James Farmar (jfarmar@nybc.org)
Wed, 11 Feb 1998 16:21:42 -0500


A customer has asked for a mannosylated peptide (sequence
DENPVVHFFKNIVTPRTPHHHHHH) and I was wondering if anyone has any input into
this procedure. I have never performed this synthesis before, but what I
would like to try is as follows: add
alpha-D-mannopyranosylphenylisothiocyanate and N-methlymorpholine to the
crude
peptide dissolved in DMSO and let it stir overnight. Then I would like to
perform a hydrolysis using Tris-HCl. Purification would be by reverse phase
HPLC and verification by MALDI-TOF MS. Does this seem correct? Any advice or
references would be greatly appreciated.
Thank You,
Dan Yoon

Derivitizing a lysine in a peptide with mannosePITC is straightforward. I
prefer to use a 1/1 mixture of 0.1 M sodium bicarbonate/DMF as per Biesson,
JBC 1996, 45, p28024. You can quench with Tris buffer. Use a 1.2 molar
excess to the amines present in your peptide. An alternative protocol can
be found in Lindhorst, Tet Lett 1997 38 p3885.

I'm not sure what you mean by "hydrolysis using Tris" but you want to avoid
any exposure to acid conditions such as 0.1% TFA. I purified my
mannosylated peptide using 50 mM TEAc or AmmAc. MALDI MS with sinapinnic
acid confirmed that I had made the right stuff.

Good luck.

Dr. Jim Farmar
MicroChemistry
L.F. Kimball Research Institute
New York Blood Center
212 570-3128
212 570-3195