I've tried to use Ripa buffer containing 0.1% SDS + 10% of proteinase inhibitors combined with 3 cycles of freeze/thaw (Dry ice with isopropanol/Dry bath 70ºC), followed by 16.000rcf for 10 minutes. My issue is, after all this process my samples look like "jelly". Has somebody experienced this issue before? How can I solve that?