The bicinchoninic acid assay (BCA assay), also known as the Smith assay, is a biochemical assay for determining the total concentration of protein in a solution (0.5 μg/mL to 1.5 mg/mL).
The Bradford protein assay is a spectroscopic analytical procedure used to measure the concentration of protein in a solution. It is subjective, i.e., dependent on the amino acid composition of the measured protein.
The Lowry protein assay is a biochemical assay for determining the total level of protein in a solution. The total protein concentration is exhibited by a color change of the sample solution in proportion to protein concentration, which can then be measured using colorimetric techniques.
1. Picric acid colorimetric assay for the quantitative determination of cyanide - for activity assays of cyanide-degrading nitrilases.
2. Indophenol blue method for the quantitative detection of ammonia/ammonium - for activity assays of nitrilases that hydrolyze higher nitriles (benzonitrile among others) resulting in the production of ammonia among other products.
To different degrees, all aromatic amino acids absorb ultraviolet light.