There are several recipes for RIPA buffer. Which recipe is the one that interferes with the enzyme activity? I suppose it's the one that lacks SDS will be good for you.

Lysing cells is not a big deal. I suggest using ultrasonication for 1-3 seconds. Do it on ice within a few seconds to avoid overheating, which may denaturize your samples' protein content.

Hi, Thanks for your suggestion. For my protein extraction, I always use sonication after adding lysis buffer. But my question was about the buffer for seperating cells from the plate and lyse them. I guess use Ripa buffer or same buffer which I use for my other protein extraction would be good if I remove IGPAl or triton.

Here is the buffer I use for extraction: 50 mM Tris (pH 7.5), 0.5

M NaCl, and 2% Igepal, 1% protease inhibitor cocktail, and 1% phosphatase inhibitor cocktailon.

500 mM NaCl seems high for a lysis buffer. Physiological is 150 mM, a hypotonic lysis buffer would have less than 50 mM. I wouldn't remove IGPAL or detergent.