Friday, November 29, 2013

How does TMT10 affect peptide charge states?

A reader wrote in with this very sensible question regarding one of my posts on the TMT 10plex reagents.  The question from Javi:  How does the new TMT 10plex reagent affect peptide charge states.  For example, he notes, that iTRAQ can lead to an increase in charge states.  The TMT0 reagent, as well, is often used in ETD studies because the charge state gets pushed up.

 But does the TMT 10plex do the same thing?  I could probably ask someone, but since I have a lot of data lying about in all of these portable hard drives, maybe I should just look at a few.  Who needs scientific rigor?  This is a blog, after all!

  Anyway, I picked two tryptic digests that each had roughly 30,000 MS/MS events, both are adherent cancer cell line digests.

The black bars are the unlabeled digest.  And the majority of the peptides appear to be +2.  The TMT labeled seems a little biased toward +3.

So, in my completely unscientific (and roughly 4 minute analysis) I'd say, yes, the TMT10 plex is similar to other isobaric peptide labels in that it tends to lead to an increase in peptide charge state.

Keep these questions coming!  Sometimes I seriously just run out of things I'm interested enough to write about!

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