BSA Standard for Protein Quantitation

Protein concentration determination is very complex and affected by many factors, such as the protein composition, conformation, and sample matrix [1]. The most often used simple method is to determine the concentration by UV absorbance at 280 nm using the Beer-Lambert Law. The 280 nm UV absorbance is mainly attributed to the number of aromatic amino acids (tryptophan and tyrosine) in the protein and is affected by protein conformation, aggregation, solvent, and pH. For many proteins, there is no experimentally determined extinction coefficient at 280 nm for the concentration determination. Other indirect protein quantitation methods, such as Bradford [2, 3] and bicinchoninic acid (BCA) assay [4] (introduced by Smith, et al. in 1985), are based on protein-dye interactions to generate a colorimetric signal. The signal also varies with protein composition and assay conditions. BSA is usually used as the standard for these assays.

The chromatographic purified BSA standard is designed for quantitation of proteins and protein conjugates by HPLC, MS, and other protein assays. This product consists of 1 mg lyophilized ultra-pure BSA that can be quickly reconstituted in 980 µL of deionized water to obtain a 1 mg/mL solution in 1x PBS buffer without any insoluble particles. CellMosaic routinely uses this product for its own internal bioconjugation-related research.

This product can be used together with the SEC (gel filtration) HPLC Protein Standard (CM92004) to better characterize proteins and bioconjugates.

Key Features of the product:
• Chromatographic purified, ≥99% of BSA content by SEC HPLC (may contain 1-3% of aggregated BSA depending on storage, preparation, and analytical method).
• Lyophilized powder ready to use after reconstitution with deionized water.

Please contact us at for specific academic pricing.