Pierce 660-nm Protein Detection Reagent is a ready-to-use detergent and reducing agent compatible reagent for rapid determination of total protein concentration. The assay is more linear than the Coomassie-based Bradford assay and is compatible with higher concentrations of most detergents, reducing agents, and other commonly used reagents.

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Features of the 660-nm protein assay kit include:
•Compatibility—compared to other dye-based assays Wider range of detergents and reducing agents available
•Ready-to-use—single reagents using a simple mix-and-read protocol; no working reagents to prepare
• Linear—Produces a more linear standard curve than using the Bradford assay
•Assay format—Can be tested in test tubes or microplates
•Samples Volume—Only 10 μL required for microplate, 100 μL required for detection tube procedure
•Storage—Store at room temperature

Auxiliary Ionic Detergent Compatibility Reagents (IDCR) offers broader detergent compatibility, making it the only protein detection method suitable for samples containing Laemmli SDS sample buffer and bromophenol blue. Although the Pierce 660-nm Protein Assay produces higher protein-to-protein variability (37%) than other assays, such as the BCA Protein Assay, the simpler single-reagent format and broader substance compatibility make the Pierce 660-nm Assay More convenient for many general applications. The Pierce 660-nm protein assay is available in tube or microplate format.

How does the Pierce 660-nm test detect protein
The Pierce 660 protein test is based on the binding of a patented dye-metal complex to protein under acidic conditions, resulting in a maximum dye absorption (measured at 660 nm) transition. The dye-metal complex is reddish-brown in color and changes to green upon binding to proteins. This color change is due to dehydrogenation of the dye at low pH, a process facilitated by the interaction of positively charged amino acid residues and negatively charged dye-metal complexes within the protein. Therefore, the dye interacts primarily with basic residues in proteins such as histidine, arginine, and lysine, and to a relatively lesser extent with tyrosine, tryptophan, and phenylalanine .

The color produced in the assay is stable and increases proportionally to a wide range of increasing protein concentrations, even in the presence of detergents and reducing agents that are incompatible with the Bradford and BCA protein assays.

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Pierce 660-nm protein detection kit (Includes protein standards)
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