Hi Heba,

we have always kept our cell lysis buffer at 4 degree. However, we add fresh protease inhibitors before use.

You can make a concentrated stock of PI (25X or 100X) and add the protease inhibitor to the amount of RIPA you need to lyse your cells. 

Dear Heba,

I have used RIPA before, but I am a bit confused about what you mean by "safely". Any how, I think it is okay for you to aliquote in eppendorfs. I think it should be fine since inside a box in a freezer/fridge they won't get much light. You can also wrap them in aluminium foil if that still worries you.

Thanks I will alliquote but have 500 ml bottle needed many hours to melt at room temp. Wondering if it is ok to put few minutes in incubator . 

Hi Heba,

we have always kept our cell lysis buffer at 4 degree. However, we add fresh protease inhibitors before use.

You can make a concentrated stock of PI (25X or 100X) and add the protease inhibitor to the amount of RIPA you need to lyse your cells. 

Heba, you may need to warm to >30C. I imagine the SDS is what is causing the apparent slow "thaw," so warming above room temp to thaw should be fine. This will allow the SDS to go back into solution.

As Nicolas has stated we also store the entire 500mL bottle at 4C with no issues. We use it for lysing cells to prepare them for Western blotting. Don't know if the original application requires different handling conditions.