Hi Leonardo,

We use the "cOmplete Protease inhibitor from Roche.  It is sold by SIGMA - see link attached to this message.  It is very easy to use and contains a wide range of inhibitors.

Best,

Hediye.

http://www.sigmaaldrich.com/catalog/product/roche/04693116001?lang=en®ion=US&cm_sp=Insite-_-prodRecCold_xorders-_-prodRecCold2-1

Dear Hediye

Thanks for you reply

The cocktail you mentioned also inhibits trypsin and chymotrypsin

My point is that I do not want to inhibit trypsin for my posterior ms analysis

Hi Leonardo,

This is the case where not using the inhibitors may result in chewed up proteins that you are trying to identify/characterize.  The specific protease eg;, trypsin is used in excess over the protease inhibitors that this may overcome the problem of inhibition of all the trypsin by the protease inhibitor cocktail. 

I typically use ~5ng trypsin /uL of the digest volume.

Best,

Hediye.

Hi Leonardo,

Do you find protease inhibitor affecting your subsequent tryptic digestion?

Thanks alot in advance