MS and HPLC:lg peptides

Katheryn Resing (Katheryn.Resing@Colorado.EDU)
Fri, 20 Feb 1998 08:54:15 +0000

In the current CNBr digestion discussion, Deb McMillen mentioned the
problem of recovering large CNBR generated peptides by RP-HPLC. Now that
mass spectrometers can more effectively analyze large peptides, we are
starting to generate larger fragments, using CNBR or tryp cleavage. We
also have run into this problem of desalting/purifying larger peptides.
These digested peptides seem to be much more difficult than the comparable
sized "standards", such as insulin and myoglobin, presumably because they
have association properties that are required for assembly of the protein
structure.

I would appreciate it if anyone who has experience purifying or running
lc/ms on large fragments from CNBr or tryp cleavage would share what resins
and buffers they have used.

We also have problems seeing these large CNBr or trp cleavage peptides out
of MALDI matrices (we are new to maldi and use the prepared matrices from
HP). I would also be interested in any hints about alternative matrices
that have worked with peptides generated by CNBr or tryp cleavage.

Thank you in advance.

Katheryn Resing