Spectroscopic characterization of Coomassie blue and its binding to amyloid fibrils
Journal article, 2012

Coomassie brilliant blue G-250 (CB) is the dye used frequently in the Bradford assay for protein concentration determination. In this study, we investigated how the solvent polarity and viscosity affect the CB absorption and fluorescence spectra and apply this understanding to investigate the binding of CB to lysozyme and insulin in the native and amyloid fibril states. Coomassie blue binds both to the native protein and to amyloid fibrils but gives distinctly different spectral responses. The absorption and fluorescence spectra of CB indicate that binding sites in the fibrils are less polar and hold the CB dye more rigidly than in the native forms. The spectral comparison of CB bound to the two different fibrils showed that the binding sites are different, and this was most likely due to differences in secondary structure as monitored by circular dichroism. Finally, linear dichroism was used to show that the fibril-bound CB is oriented preferentially parallel to the insulin amyloid fibril axis.

Coomassie blue


Bradford assay

Amyloid fibrils




Nils Carlsson

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Catherine Kitts

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Björn Åkerman

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Analytical Biochemistry

0003-2697 (ISSN) 1096-0309 (eISSN)

Vol. 420 1 33-40

Subject Categories

Physical Chemistry

Analytical Chemistry


Basic sciences

Areas of Advance

Life Science Engineering (2010-2018)



More information