BCA Protein Assay Reagent A is a component of the Pierce BCA Protein Quantitative Assay Kit, which is a two-component, Highly accurate, detergent-compatible detection reagent for determination of total protein concentration compared to protein standards. Pierce BCA reagents provide accurate determination of protein concentration for most sample types encountered in protein research. The Pierce BCA assay can be used to evaluate the yield of whole cell lysates, affinity column separation fractions, purified protein samples, and monitor protein contamination in industrial applications. Compared to most dye-binding methods, the BCA protein quantification method is less affected by differences in protein amino acid composition and therefore has higher protein-to-protein quantitative consistency.

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Pierce BCA Protein Assay Kit (Reagents A and B) features include:
•Colorimetric Measurements< /b>—can be evaluated visually or measured using a standard spectrophotometer or microplate reader (562 nm)
• Highly consistent—compared to the dye binding method (Bradford) Less protein-to-protein variation
• High compatibility—performance is not affected at concentrations common to most ionic and non-ionic detergents
• Quantification time — 30-minute incubation; easier to operate and 4 times faster than traditional Lowry method
• Detection Range—BSA has a linear working range of 20 to 2000 µg/ mL
• High Sensitivity—Use enhanced protocol to detect samples with concentrations as low as 5 µg/mL

How the assay works
BCA The protein detection method uses protein to reduce Cu²⁺ to Cu¹⁺ in an alkaline environment, and then uses bicinchoninic acid (BCA) to detect cuprous cations. (Cu¹⁺). The first step is for copper to chelate with proteins in an alkaline environment to form a light blue complex, a process known as the biuret reaction. In this reaction, known as the biuret reaction, peptides containing three or more amino acid residues form colored chelate complexes with copper ions in an alkaline environment containing sodium potassium tartrate.

In the second step of the color reaction, BCA reacts with the reduced (cuprous) cation formed in the first step. Two molecules of BCA chelate with a cuprous ion, producing a deep purple reaction product. The BCA/copper complex is water-soluble and has strong linear absorbance at 562 nm, which increases with increasing protein concentration. The sensitivity (lower detection limit) of this complex is approximately 100 times that of the light blue in the first reaction.

The reaction is greatly affected by the four amino acid residues (cysteine, cystine, tyrosine and tryptophan) in the protein's amino acid sequence. However, unlike the Coomassie dye binding method, the universal peptide backbone also affects color formation, helping to minimize variability due to differences in protein composition.

Related products
Pierce BCA Protein Quantitative Analysis Kit< /a>
Pierce BCA Protein Detection Reagent B
Pierce BCA solid