Mass difference of -60.7?

Dr. Artem Evdokimov eudokima at mail.ncifcrf.gov
Mon Apr 30 11:53:10 EST 2001


What MS method did you use ? Does N correspond to the expected molecular
mass of any kind of a fragment ? What cleavage methods did you use ?
(Your fragments may very well be all chemically modified, and then the
N-60.7 would be a small fraction of the unmodified peptide fragment).
List all the chemicals that have come in contact with your peptide.

If you provide more details, we might be able to help you better.


Luc CAMOIN wrote:
> Hi
> I have a synthetic peptide of 28 AA's. I run different cleavage and
> then separation of the resulting fragments on reverse phase HPLC in
> H2O/CH3CN gradient including 0.1%TFA.  Then the fractions were
> lyophilized.
> When I run the mass spect, I found some fragments showing a doublet at
> mass N for the major peaks and N -60.7 for the minor peaks. What could
> this -60.7 be?
> Does anyone have any explanation about this -60.7?
> Thanks in advance

|Dr. Artem Evdokimov   Protein Engineering |
| NCI-Frederick        Tel. (301)846-5401  |
|              FAX (301)846-7148           |
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