does 1% SDS prevents proteases? - (Jul/06/2009 )
Dear All
a colleague claims that 1% SDS in lysis buffer is sufficient to inhibit proteases and there is no need to use protease inhibitors. is this correct?
yobou on Jul 6 2009, 07:56 PM said:
a colleague claims that 1% SDS in lysis buffer is sufficient to inhibit proteases and there is no need to use protease inhibitors. is this correct?
At least Proteinase K is not inhibited...
It is false - SDS is a detergent, it primarily dissolves lipids rather than proteins.
Proteinase K's activity is actually enhanced by SDS: "Activity can be stimulated by addition of denaturing agents (SDS and urea)" (see here, under "Activators").
HomeBrew on Jul 7 2009, 12:23 PM said:
I mean proteases in human cancer cells (serine, cysteine and aaspartate , ...etc proteaes) . I guess proteinaseK is not among them.
Proteinase K is a serine protease from a eukaryotic organism...
Regardless, in answer to your question -- I don't think 1% SDS is effective enough to rely on it alone for protease inhibition.
Ask your colleague for the data.
GeorgeWolff on Jul 8 2009, 06:36 PM said:
actually before I open this topic for discussion I did so, and he showed me a blot for a protein that is clealry upregulated by certain drug treatment as a positive control. That is why I was asking whether this method is valid or not.
is there any reason you wish to avoid habitual protease inhibitors?