Radioimmunoprecipitation assay buffer (RIPA buffer) is a lysis buffer used to lyse cells and tissue for the radio immunoprecipitation assay (RIPA). This buffer is more denaturing than NP-40 or Triton X-100 because it contains the ionic detergents SDS and sodium deoxycholate as active constituents and is particularly useful for disruption of nuclear membranes in the preparation of nuclear extracts. The RIPA buffer gives low background but can denature kinases.