Protein Assay Kits

A number of assays are available for the determination of protein concentration, each with a set of advantages. The Bio-Rad protein and Quick Start™ Bradford protein assays are recommended for classroom use.

Bio-Rad Protein Assay Kit

The simplicity, sensitivity, and color of the Bio-Rad protein assay make it a great vehicle for integrating biology, math, experimental design, and technique. The assay is derived from the Bradford method (1976) and is based on the color change of Coomassie (Brilliant) Blue G-250 dye in direct response to various concentrations of protein. In a typical application, the protein assay reagent is added to a sample and the color change is quantitated with a spectrophotometer or microplate reader. Protein standards provided in this kit allow generation of a standard curve based on the color intensities by known concentrations of protein. The amount of protein in an unknown sample can also be accurately estimated by eye, making this a great low-tech alternative for the classroom. Advantages of the Bio-Rad protein assay kit include:

• Storage up to 1 year at recommended 4°C
• Protein standard included
• Rapid and sensitive
• Classroom alternative to Biuret reagent

Quick Start Bio-Rad Protein Assay Kit

The Quick Start Bradford protein assay quantitates your samples quickly so you can move on with your experiments. The ready-to-use Quick Start assay provides excellent linearity, compatibility with a wide range of reagents, and convenient features such as:

• Prediluted standards
• 1x dye reagent
• Screwcap vials instead of ampoules
• Standard microplate and microassay protocols

References

Bradford MM (1976). A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72, 248–254.