Measurement of protein using bicinchoninic acid

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Protein quantification is essential in biological research.
• Existing methods like the Lowry assay have limitations regarding interferences and protocol complexity.

Purpose of the Study:

• To introduce and validate a novel protein quantification method using bicinchoninic acid.
• To compare the performance of this new assay against the established Lowry method.

Main Methods:

• Utilizing bicinchoninic acid, sodium salt, to form a stable, intense purple complex with cuprous ion (Cu1+).
• Monitoring cuprous ion produced during the reaction of protein with alkaline Cu2+ (biuret reaction).
• Assessing the assay's tolerance to common interferences such as nonionic detergents and buffer salts.

Main Results:

• The bicinchoninic acid assay produces a stable, proportional color change with increasing protein concentrations.
• The assay exhibits greater tolerance to nonionic detergents and buffer salts compared to the Lowry method.
• The method allows for simplified, one-step analysis with enhanced protocol flexibility.

Conclusions:

• The bicinchoninic acid assay provides a sensitive and reliable alternative for protein quantification.
• This method maintains high sensitivity and low protein-to-protein variation, similar to the Lowry technique.
• Its improved tolerance to interferences and simplified protocol enhance its utility in various research settings.