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Lowry Assay

A biochemical assay for determining the total level of protein in a solution. The method is based on the reaction of protein molecules with copper under alkaline conditions, followed by the reduction of the Folin-Ciocalteu reagent, leading to a colorimetric change that is directly proportional to the protein concentration.

Workflows Requiring the Lowry Assay:


How to Perform a Lowry Assay


1. Preparation of Reagents


2. Sample and Standard Preparation


3. Addition of Alkaline Copper Solution


4. Addition of Folin-Ciocalteu Reagent


5. Measurement of Absorbance


6. Calculation of Protein Concentration


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Considerations and Limitations of Lowry Assay


Alternatives to Lowry Assay

The Bradford and Bicinchoninic Acid (BCA) assays are two modern alternatives to the Lowry assay, offering simpler protocols and greater compatibility with various substances. The Bradford assay is favored for its rapid, one-step process, ideal for higher protein concentrations but sensitive to detergent presence. In contrast, the BCA assay, while slightly more complex, is more tolerant of detergents and reducing agents, making it suitable for a broader range of protein concentrations.