I performed a deproteinization of my biopolysaccharide and performed a Bradford assay on the native and deproteinized versions of the polymer to quantify purification yield.
What happened is that the deproteinized polymer contains MORE protein than the native polymer, as inferred by its higher absorbance at 595nm post-Bradford.
Is there any sort of interference that may cause this? Because I checked UV-VIS earlier and the 280 nm protein band disappeared in the deproteinized polymer.
Dear Bruno M. Guerreiro, please check the following documents. My Regards
https://www.researchgate.net/publication/260430229_Quantitative_high_throughput_analytics_to_support_polysaccharide_production_process_development
https://link.springer.com/article/10.1134/S1068162015020119
Assuming that you haven't added an enzyme to achieve deproteinisation, then yes, Bradford has problems in accurate quantification. I have found by empirical analysis that achieving an optical density value of 0.4 for each sample provides a reasonably accurate value of soluble protein. Obviously, if the portein is insoluble then it will not be detected by Bradford.
Check the deproteinazation procedure. If it contains detergent, then this is the main weakness of Bradford assay as it causes false positive reaction with detergents.
check Table 1 in the following protocol for possible interferences;
https://www.bio-rad.com/webroot/web/pdf/lsr/literature/4110065A.pdf
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