Thursday, December 5, 2013
PRTC. I swear I wrote this entry once before!
Are you running some sort of quality control when you do proteomics? If your answer is "of course" then I like you. Heck, I'm a friendly guy. If your answer was "never, and I hate pugs!" I'd probably still like you, but I might like you better if you are running some sort of QC.
We need to have some sort of metric of how our instruments are running. I'm often asked what my favorite is. This question commonly comes after people find out that I don't know what a BSA digest should look like...
The answer, and I swear I wrote all of this a long time ago, is PRTC.
PRTC? Now, I'll admit, I didn't know about this thing until I joined Thermo. But I like it so much that I keep aliquots in the ziplock baggy that I keep my toothpaste in for when I travel.
PRTC stands for "Pugs Rock The Cazbar!"
or Peptide retention time calibration....
What it is: A clean, equimolar, mixture of 15 isotopically labeled peptides for varying hydrophobicity. Running these can give you a picture of the performance of your LC gradient and your signal intensity over time. Since they are isotopically labeled you don't have to worry about them being mistaken for something else if you happen to have a small fraction carry over into your next run.
They are also well aliquoted. So you can use them as spiked in standards at low concentration to normalize label free peptide quan from sample to sample. (I should have some nice data on this in the next couple of weeks.) And in Pinpoint, you can simply add in QC peptides and it throws them in.
Oh. And it's cheap.
Downside? None. Period. Exclamation point.
Want to know more? Check out the product page at Pierce, or this sweet application note written by some of my favorite people!