Prince:Phosphopeptide Enrichment

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(New page: =Brief Introduction= http://en.wikipedia.org/wiki/Phosphorylation Phosphorylation is the most common [http://en.wikipedia.org/wiki/Posttranslational_modification post-translational mo...)
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=Brief Introduction=
=Brief Introduction=
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[[http://en.wikipedia.org/wiki/Phosphorylation Phosphorylation]] is the most common [http://en.wikipedia.org/wiki/Posttranslational_modification post-translational modification].
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[[http://en.wikipedia.org/wiki/Phosphorylation Phosphorylation]] is the most common [http://en.wikipedia.org/wiki/Posttranslational_modification post-translational modification]. Phosphorylation changes the a peptides molecular weight by about 80 mass units.  This change is clearly discernible using mass spectrometry, but the negative charge on the phosphate group decreases the peptides charge state.  Peptides with lower charge states are not as easily fragmented for MS2, and when a peptide becomes neutral or negative it cannot be read by the mass spectrometer at all.  Also, the percent of phosphorylated peptides in a cell is very low compared to the percent of dephosphorylated peptides, and the mass spectrometer only selects the most abundant peptides for MS2 identification.  Therefore, phosphopeptides are rarely identified with high confidence in complex samples.  Fortunately techniques have been developed to isolate phosphopeptides from complex samples.
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Revision as of 01:37, 7 February 2012

Brief Introduction

[Phosphorylation] is the most common post-translational modification. Phosphorylation changes the a peptides molecular weight by about 80 mass units. This change is clearly discernible using mass spectrometry, but the negative charge on the phosphate group decreases the peptides charge state. Peptides with lower charge states are not as easily fragmented for MS2, and when a peptide becomes neutral or negative it cannot be read by the mass spectrometer at all. Also, the percent of phosphorylated peptides in a cell is very low compared to the percent of dephosphorylated peptides, and the mass spectrometer only selects the most abundant peptides for MS2 identification. Therefore, phosphopeptides are rarely identified with high confidence in complex samples. Fortunately techniques have been developed to isolate phosphopeptides from complex samples.

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