Western Blotting

Protein Quantification Assay Optimization

Selecting the Right Assay Type

Total protein assays measure the total amount of protein in a sample, most commonly by changing the optical density of the sample in proportion to the concentration. By creating a standard curve based off of the changes of optical density in samples of known concentration, it is possible to calculate the protein concentration in any sample.

One of the first issues to consider when conducting a total protein assay is the type of assay to use. A primary factor to consider in making your choice is the compatibility of the assay with the samples. The objective is to select an assay that requires the least manipulation or pre-treatment of the samples, and will give good results for your sample type.

Use this comparison chart to help decide which protein assay is right for you

Assay kit Advantages Disadvantages
Coomassie Plus Protein Assay Kit Fast, compatible with reducing agents Incompatible with detergents, yeilds poor resutls with very low concentrations
BCA Protein Assay Kit Compatible with detergents and denaturing agents, low variability Incompatible with reducing agents
Micro BCA Protein Assay Kit High sensitivity and precision Sensitive to copper reductants and chelating agents

Keywords: Western blotting optimization, total protein analysis, protein quantification assay, BCA, commassie, protein silver

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