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The Bicinchoninic Acid (BCA) Assay for Protein Quantitation

  • John M. Walker
Part of the Methods in Molecular Biology™ book series (MIMB, volume 32)

Abstract

The bicinchoninic acid (BCA) assay, first described by Smith et al. (1) is similar to the Lowry assay, since it also depends on the conversion of Cu2+ to Cu+ under alkaline conditions (see  Chapter 1). The Cu+ is then detected by reaction with BCA. The two assays are of similar sensitivity, but since BCA is stable under alkali conditions, this assay has the advantage that it can be carried out as a one-step process compared to the two steps needed in the Lowry assay. The reaction results in the development of an intense purple color with an absorbance maximum at 562 nm. Since the production of Cu+ in this assay is a function of protein concentration and incubation time, the protein content of unknown samples may be determined spectrophotometrically by comparison with known protein standards. A further advantage of the BCA assay is that it is generally more tolerant to the presence of compounds that interfere with the Lowry assay. In particular it is not affected by a range of detergents and denaturing agents such as urea and guanidinium chloride, although it is more sensitive to the presence of reducing sugars. Both a standard assay (0.1–1.0 mg protein/mL) and a microassay (0.5–10 µg protein/mL) are described.

Keywords

Absorbance Maximum Standard Assay Unknown Sample Bicinchoninic Acid Similar Sensitivity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Smith, P. K., Krohn, R. I., Hermanson, G. T., Mallia, A. K., Gartner, F. H., Provenzano, M. D., Fujimoto, E. K., Goeke, N. M, Olson, B. J., and Klenk, D. C. (1985) Measurement of protein using bicinchoninic acid. Anal. Biochem. 150, 76–85.PubMedCrossRefGoogle Scholar
  2. 2.
    Kessler, R. J. and Fanestil, D. D. (1986) Interference by lipids in the determination of protein using bicinchoninic acid. Anal. Biochem. 159, 138–142.PubMedCrossRefGoogle Scholar
  3. 3.
    Hill, H. D. and Straka, J. G. (1988) Protein determination using bicinchoninic acid in the presence of sulfhydryl reagents. Anal. Biochem. 170, 203–208.PubMedCrossRefGoogle Scholar
  4. 4.
    Morton, R. E. and Evans, T. A. (1992) Modification of the BCA protein assay to eliminate lipid interference in determining lipoprotein protein content. Anal. Biochem. 204, 332–334.PubMedCrossRefGoogle Scholar
  5. 5.
    Akins, R. E. and Tuan, R. S. (1992) Measurement of protein in 20 seconds using a microwave BCA assay. BioTechniques 12(4), 496–499.PubMedGoogle Scholar

Copyright information

© Humana Press Inc., Totowa, NJ 1994

Authors and Affiliations

  • John M. Walker
    • 1
  1. 1.Division of BiosciencesUniversity of HertfordshireHatfieldUK

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