>Amanda,
>
>Your protein may be glycosilated at the N-terminal. If the first four
>aminoacids are glycosilated you cannot see them in the chromatograms,
because
>they elute outside the gradient region. In this case, the 5th residue
appears
>like a typical 1st cycle. The other possibility is that the first four
>aminoacids are unusual, falling in uncommon regions of the chromatogram.
But
>this is much less probable.
>
>Ricardo.
>
>Amanda Hall wrote:
>>
>> Hi everyone,
>>
>> I just put a sample (short tryptic peptide on a Biobrene treated filter)
on
>> the protein sequencer and saw nothing for the 1st 4 residues. Then
suddenly
>> in the 5th residue cycles numerous AA's appeared and I am now getting
>> sequence. The 5th residue looked very much like a typical 1st residue
cycle
>> with high levels of Glu and gly. Has anyone ever seen this before and
what
>> causes it?
>>
>> thanks a lot
>>
>> Amanda Hall
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Ricardo Bastos Cunha
>Brazilian Center of Protein Core Facilities and Research - UnB
>mailto:rbcunha@unb.br
>http://www.unb.br/cbsp/CBSP.html
>http://www.geocities.com/Athens/Acropolis/5221
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