Question

Why would it be difficult to apply the Coomassie Blue quantitative test to the fingernail?

Answer 1

Coomassie Blue quantitative test, also known as the Bradford protein assay is based on the absorbance shift of Coomassie Blue dye. Under acidic conditions, the red form of the dye is converted into a blue form on binding with the protein being assayed. Being a absorbance based test dependant on the protein and dye binding, there are some obvious disadvantages.

It depends on the sequence of the protein. If the protein does not contain the specific number of residues, the dye will not be able to bind to the protein effectively. You also have to compare the absorbance of the protein to that of a standard protein. So if the protein does not react to the dye in a similar way as the standard protein, the result may be faulty. This is observed in case of Keratin which is present in the fingernails which makes the application of coomassie blue test difficult.