Adaptation of the dye-binding protein assay to microtiter plates.

The dye-binding protein assay has been adapted for use with microtiter plates and a plate reader. The total volume of the assay was reduced to 0.2 ml, with equal volumes of sample and diluted dye reagent being used. Because of the small volume, the assay is conservative of both protein sample and reagent. The use of microtiter plates allows the absorbance of samples to be read using a plate reader, markedly reducing the time needed for evaluating sample absorbances. This assay is quite sensitive, with a limit of less than 0.5 micrograms bovine serum albumin. In addition, the assay has been calibrated with homogeneous nitrate reductase. The response of nitrate reductase in the assay is about 70% of that of the standard protein, bovine serum albumin. The response of several other proteins was evaluated and the differences in response are discussed.