A METHOD FOR PROTEIN ASSAY IN LAEMMLI BUFFER

A simple, cheap, and rapid assay for soluble and membrane-bound protein solubilized in Laemmli sodium dodecyl sulfate sample buffer is described. Following the addition of trichloroacetic acid to a final concentration of 24%, the induced turbidity was measured at 570 nm in a microplate reader, after an incubation period of approximately 10-30 min. The assay is suitable for measuring bovine serum albumin at a concentration of 15 to 500 mu g/ml in Laemmli buffer, corresponding to 2 to 75 mu g protein per well on the microtiter plate. Other nonproteinaceous macromolecules in the sample may introduce an error. (C) 1994 Academic Press,Inc.