We have a DCCD-labeled protein and are trying to identify the modified
residue(s). Using 14C-DCCD we have overlapping trypsin/BrCN fragments which
light up on an autoradiograph, and the sequence shows candidate residues.
But we have a problem. We have transferred the bands onto PVDF (the label
is still there) and used them to generate aminoacid sequence data,
collecting the fractions off the HPLC to try and idetify the residue
unambiguously. But we can't see the expected counts.
Does anyone have any suggestions where the counts might have gone? We think it
unlikely that they are still on the column.
Robin Walters. Robert Hill Institute, Sheffield UK.