The biuret reaction can be used to assess the concentration of proteins because peptide bonds occur with the same frequency per amino acid in the peptide.
12.
Since biuret has the formula NH 2-CO-NH-CO-NH 2, that suggested the presence of similar peptide bonds in proteins.
13.
The reagent is commonly used in the biuret protein assay, a colorimetric test used to determine protein concentration by UV / VIS spectroscopy at wavelength 550 nm.
14.
I know Biuret Reagent turns violet in the presence of protein, but amino acids make up proteins, so will they change color ? Preceding talk ) 00 : 50, 8 October 2010 ( UTC)
15.
Other experiments you can do with copper sulfate solution are : add ammonia to get a dark blue solution which can dissolve cotton, add biuret to get a different dark blue solution, add a base like sodium bicarbonate to make a precipitate.
16.
The water-soluble BCA / copper complex absorbs much more strongly than the peptide / copper complex, increasing the sensitivity of the biuret test by a factor of around 100 : the BCA assay allows to detect proteins in the range of 0.0005 to 2 mg / mL ).
17.
I didn't dig for the best sources, but to quote, " Dipeptides, single amino acids ( except serine and threonine ), urea, and ammonia give blue solutions, which are negative tests " and in a historical source, [ http : / / books . google . com / books ? id = ztDqAAAAMAAJ & pg = PA11 " According to Schiff, the red coloration is caused by the formation of a copper potassium biuret compound.
