Proteinase K and SDS? - (Jun/02/2007 )

I am following an experiment done in a paper where they have treated whole cells of bacteria with Proteinase K to check if the protein of interest is attached to cell surface or is it located in the cell and with one set of samples they even add 1% SDS. Now, do you have any idea what is the purpose of SDS here? I've read somewhere that Proteinase K is stable even when this amount of SDS is added. Do they add it in order to destroy the probable linkage of the protein to the cell membrane, to help the cleavage by Proteinase K?

AFAIK SDS disrupts the membranes.

SDS is there for disturbing membranes.
So if the protein is not degraded in the membrane + Prot K sample but degraded in membrane + Prot K + SDS, then your protein is in membranes.
May you tell me (or pm it) the reference where you saw that "I've read somewhere that Proteinase K is stable even when this amount of SDS is added"?
good luck with your exp