CB X™ Protein Assay

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Protein assays are routinely used in many research fields to estimate proteins in a vast array of buffers and conditions. A major problem for researchers is to select a protein assay from the vast selection on the market that is compatible with their protein sample. CB-X™ Protein Assay eliminates this problem as it is designed to be compatible with all commonly used buffers and conditions in protein isolation, storage and assays. 

For protein samples in simple, uncomplicated, aqueous buffers, CB-X™ is a highly sensitive, single reagent assay that can be performed in 5 minutes. CB-X™ Protein Assay uses a protein dye that is an improvement on the Bradford Coomassie dye reagent (Figure 1)

 

For complicated protein samples, CB-X™ Protein Assay is supplied with reagents to clean up the samples and remove all reagents and chemicals that interfere with accurate protein estimation (figure 1). These reagents include detergents, chaotropes, reducing agents, alkylating agents, sugars, high salt concentrations, buffering agents and chelating agents (Table 1). The clean up stage and subsequent protein assay is performed in a single tube to ensure no protein loss and to maintain the accuracy of the assay. Figure 2 demonstrates the effect of CB-X™ in the presence of 1% Triton® X-100 or 1% SDS. 

If the protein sample does not contain interfering agents, then a straightforward, single reagent assay is performed to give a linear response. If interfering agents are present or if artifactual results are produced, then the protein samples are treated with the clean up reagents and the protein is assayed to generate a linear response.

CB-X™ Protein Assay is supplied with lot-specific CB-X™ Tables. These allow researchers to perform single protein clean ups, subsequent assays, and then look up their absorbance in the CB-X™ Table to find the protein concentration. The CB-X™ Table eliminates the need for multiple protein standards and saves considerable time and effort. The table is prepared with a complex protein mixture that compares well with proteins from mammalian, plant, bacteria and yeast sources. The assay is supplied with a BSA protein standard or a non animal protein standard  with Cat. # 786-12X or 786-894 respectively for generating curves when using CB-X™ Assay Dye alone or for researcher’s who prefer to generate their own standard curve or their own CB-X™ Table per their specific conditions.

 

Table 1: CB-X™ Protein Assay is compatible with many interfering agents 

DETERGENTS		REDUCING AGENTS
Brij® 35	2%	2-mercaptoethanol	1M
CHAPS	2%	DTT	1M
CHAPSO	2%	CHAOTROPES
Nonidet® P-40	2%	Guanidine.HCl	6M
SDS	2%	Urea	6M
Triton® X-100	2%	SALTS
Tween® 20	2%	Ammonium sulfate	1M
Deoxycholate	0.1%	MISCELLANEOUS
SUGARS		EDTA	0.1M
Glucose	1M	HEPES	0.1M
Sucrose	25%	MES	0.1M