Protein Quantitation

Protein Quantification is the determination of the concentration of protein in a solution. Accurate and sensitive protein quantification is important before protein analysis, particularly for comparative techniques. Colorimetric assay procedures include BCA (Bicinchoninic acid) assay, Bradford assay, and others. Sigma-Aldrich offers a variety of products for protein quantification for biochemical research.

Sigma’s Bicinchoninic Acid products offer simple, sensitive, colorimetric assay for proteins. Bradford assay products are based on complexing proteins with a dye. Bicinchoninic acid is a highly specific chromogenic reagent for Cu(I). Copper(II) sulfate solution can be used for determination of total protein, since proteins reduce alkaline Cu(II) to Cu(I) in a concentration-dependent manner. Sigma-Aldrich also offers protein standards for the BCA method. Sigma’s Bradford reagent can be used to determine the concentration of proteins in solution. It is ready to use, resistant to reducing agents (unlike BCA), and adaptable for use in microwell plates.

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B9643 Bicinchoninic Acid solution
BCA1 Bicinchoninic Acid Kit for Protein Determination for 200-1000 μg/ml protein
B6916 Bradford Reagent for 0.1-1.4 mg/ml protein
C2284 Copper(II) sulfate solution 4 % (w/v) (prepared from copper (II) sulfate pentahydrate)
P0914 Protein standard Micro Standard, liquid
P0834 Protein standard liquid, 2 mg protein/ml
QPBCA QuantiPro BCA Assay Kit for 0.5-30 μg/ml protein