"Based on results obtained on the recombinant 30 kD protein, the submitted
data sets argue persuasively that there is no significant difference in the
overall effectiveness of PVDF and in-gel approaches to internal sequencing.
Rather, the choice between these two approaches would seem to rest largely
with personal preference ..."
Similarly, the following quote (from the in press Encyclopedia of
Bioprocess Technology
John Wiley & Sons) summarizes the results of both the 1996 and 1997 studies
"Finally, the answer to the question of which approach (in-gel or on PVDF
digestion) is best to take for internal protein sequencing is that the two
methods appear to be quite comparable. That is, when peptide recoveries
are calculated from the Edman sequencing yields divided by the amount of
protein in the stained gel or PVDF band (as opposed to the amount that was
loaded onto the gel), the target peptide recoveries for both PVDF and gel
samples were just above 20% in the 1997 study (Table 3). The optimal
method for a specific project depends upon the protein of interest and the
personal preferences and level of expertise that the core lab to whom the
sample will be submitted has with each of these approaches. Based on two
ABRF studies, each of which involved 40 core laboratories, we conclude
that if a 50 pmol protein sample is subjected to SDS PAGE and then prepared
according to the protocol recommended by the core laboratory to which the
sample will be submitted, the probability of obtaining internal peptide
sequences is likely to be much higher than 83%."
Ken Williams