Determining The Concentrations Of Proteins Is Necessary For A Variety Of Different Reasons

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Determining the concentrations of proteins is necessary for a variety of different reasons. For example, protein concentration must be known in order for proteins to be used in enzyme reactions, as the correct stoichiometry must be known. Another example is protein purification; during protein purification the quantity of protein present must be known to determine the yield1. The quantification of proteins is determined by methods known as protein assays. There are different protein assays used to determine the concentration of proteins. Three different types of protein assays used by biochemists include the Bicinchoninic Acid (BCA) protein assay, Modified Lowry protein assay, and the o-Phthalaldehyde (OPA) Fluorescent Protein Assay2.
The BCA assay utilizes the reduction of Cu2+ to Cu+ from the protein. The Cu+ is then detected with the Bicinchoninic Acid. The process proceeds by the Cu2+ be reduced to Cu+ by the protein’this step of the process takes place in a basic envrioment. Next, the Cu+ forms a complex with two equivalents of Bicinchoninic Acid. The formation of the complex creates a purple solution that can be measured at a wavelength between 550 nm and 570 nm. The BCA has both adavatages and disadvantages. The main advantage is the fact that the assay can work with most types of surfactants and is easy to perform. The issue with the BCA Assay is that substances that reduce copper will also produce color changes, this could potentially lead to…

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