The Pierce Protein Assay is a method of
protein quantification. It provides quick estimation of the
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
amount in a given sample.
Protocol
The
assay
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a ...
is separated into three main parts:
preparation of the Diluted
Albumin
Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...
(BSA) Standards,
preparation of the
bicinchoninic acid
Bicinchoninic acid is a weak acid composed of two carboxylated quinoline rings.
Bicinchoninic is an organic compound with the formula (C9H5NCO2H)2. The molecule consists of a pair of quinoline rings, each bearing a carboxylic acid group. Its s ...
(BCA) working reagent,
and quantification of proteins (using either
test tube
A test tube, also known as a culture tube or sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom.
Test tubes are usually placed in s ...
or
microplate
A microplate, also known as a microtiter plate (''Microtiter'' is a registered trademark in the United States, therefore it should not be used generically without attribution), microwell plate or multiwell, is a flat plate with multiple "wells" ...
procedure).
Advantages and disadvantages
Advantages
This method is able to detect as low as 25 μg/ml and up to 2000 μg/ml of protein in a 65 ul sample, using standard protocol.
This method may be preferred for samples containing
detergent
A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more ...
s or other
reducing agent
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ).
Examples of substances that are commonly reducing agents include the Earth meta ...
s.
This method has a fast detection speed and low protein-to-protein variability in comparison to the
BCA or
Coomassie (Bradford) Assays.
This method has a stable end point.
Disadvantages
This method has greater protein-to-protein variability than the
BCA Assay.
References
{{Analytical reagents
Biochemistry methods
Chemical tests