How does the BCA-RAC compare with the original BCA assay?
The BCA-RAC provides the advantages of the original BCA assay (compatibility with detergents, buffer/salts and solvents) combined with reducing agent compatibility at concentrations routinely used in protein sample buffers. The BCA assay is based on reduction of Cu+2 to Cu+1 by proteins in an alkaline solution and the subsequent complexing of the Cu+1 to BCA reagent, yielding a purple color detectable at 562nm. Disulfide reducing agents such as DTT, 2ME and TCEP are also capable of reducing Cu+2 to Cu+1. To minimize their reducing effect, a compatibility reagent that modifies disulfide reducing agents is added to the sample before performing the assay.
What formats are available for the BCA-RAC?
There are two different formats: the BCA Protein Assay Kit - Reducing Agent Compatible (#23250) for microcentrifuge tube (1.5ml) assays and Microplate BCA Protein Assay Kit - Reducing Agent Compatible (#23252) for 96-well plates. The tube assay is compatible with 5mM DTT, 10mM TCEP and 35mM 2ME, and the microplate assay is compatible with 5mM DTT, 10mM TCEP and 25mM 2ME.
Can I increase the volumes of the sample and compatibility reagent in the microplate assay?
No. Increasing the sample and compatibility reagent volumes will require increasing the BCA working reagent, resulting in a volume that exceeds the well capacity. There must be space remaining in the well to allow mixing and prevent the solution from contacting the sealing tape.
How many assays can be performed with each kit?
The BCA Protein Assay Kit - Reducing Agent Compatible (#23250) has sufficient reagents for 250 samples or standards of 25µl each, and the Microplate BCA Protein Assay Kit - Reducing Agent Compatible (#23252) can be used to assay 1,000 samples or standards of 9µl each.
Can the compatibility reagent be stored after reconstitution and reused?
The reconstituted compatibility reagent is stable for 8 hours when stored at 4°C protected from light.