For discussion of metastable fragments from phosphorylated peptides (Sp,
Tp, Yp) see paper by
(1) Annan, R. S.; Carr, S. A. "Phosphopeptide analysis by matrix-assisted
laser desorption Time-of-Flight Mass Spectrometry" Anal.Chem. 1996, 68,
3413-3421.
Good luck,
Paul
>We have noticed that since installing delayed extraction on our MALDI-Tof
>instrument, reflectron analyses of phosphoserine and phosphothreonine
>containing synthetic peptides give a low amount of the characteristic -97
>dalton ion, with a more predominant peak at -88.3 to -88.9 daltons. Have
>others seen this latter ion as well and does anyone have an explanation for
>its origin?
>
>Thanks,
>
>Kathy Stone/Ken Williams
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Paul T. Jedrzejewski, Ph.D.
Barnett Institute
341 Mugar Bldg.
Northeastern University
360 Huntington Ave.
Boston, MA 02115
phone: 617.373.2857
fax: 617.373.2855 http://www.barnett.neu.edu
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