Bradford assay
Proteins are large biological molecules that are made up of one or more chains of amino acids. Proteins perform many different functions within a living organism, such as catalysing metabolic reactions, replicating DNA, responding to stimuli, and transporting molecules from one location from another. All proteins differ from each other primarily by their sequence of amino acids which is usually determined by a nucleotide sequence of their genes, resulting in a three-dimensional fold that determines their function.
The measurement of protein concentration is one of the most common and accurately performed biochemical assays in many fields of protein study. An assay which has been formerly described by Bradford has become the most favoured method for determining protein throughout many laboratories. It is used broadly within the food industry, by research laboratories, and in medical diagnostics.
The Bradford assay is dependent on the binding of the dye Coomassie Blue G250 to protein (mainly arginine), in which the dye is equal to the protein concentration. When the protein is absent, the solution is a red-brown colour and when the protein binds, the pKa of the dye moves causing the dye to become blue. The anionic blue form of the dye, which binds to the protein, has a maximum absorbance of 590 nm whereas the assay reagent solution of red and green forms has a maximum absorbance of 470 nm and 650 nm. Due to the assay being sensitive with a range of 20 to 200 μg protein, it can be determined by the amount of dye present in the blue ionic form. This can usually be accomplished by measuring the solution at an absorbance of 595 nm.
Proteins can usually be obtained from renal ultrafiltration. Proteinuria, a high level of protein in urine, is an indicator of a varied amount of diseases that can affect the kidney. Hypertension is a well-known common cause of kidney disease and if controlled successfully, it can lead to a decrease in proteinuria and an overall
The measurement of protein concentration is one of the most common and accurately performed biochemical assays in many fields of protein study. An assay which has been formerly described by Bradford has become the most favoured method for determining protein throughout many laboratories. It is used broadly within the food industry, by research laboratories, and in medical diagnostics.
The Bradford assay is dependent on the binding of the dye Coomassie Blue G250 to protein (mainly arginine), in which the dye is equal to the protein concentration. When the protein is absent, the solution is a red-brown colour and when the protein binds, the pKa of the dye moves causing the dye to become blue. The anionic blue form of the dye, which binds to the protein, has a maximum absorbance of 590 nm whereas the assay reagent solution of red and green forms has a maximum absorbance of 470 nm and 650 nm. Due to the assay being sensitive with a range of 20 to 200 μg protein, it can be determined by the amount of dye present in the blue ionic form. This can usually be accomplished by measuring the solution at an absorbance of 595 nm.
Proteins can usually be obtained from renal ultrafiltration. Proteinuria, a high level of protein in urine, is an indicator of a varied amount of diseases that can affect the kidney. Hypertension is a well-known common cause of kidney disease and if controlled successfully, it can lead to a decrease in proteinuria and an overall
Cited: