Bovine Serum Albumin

Bovine serum albumin (BSA) is a 66 kDa globular protein crucial for transporting molecules like fatty acids, drugs and hormones from the bloodstream. BSA is a drug carrier for bioactive compounds and has wide clinical applications. BSA has extensive usage in biological research including cell culture, molecular biology, protein biochemistry, and detection techniques. It has wide pharmaceutical applications due to ease of production and interaction flexibility.

Bovine serum albumin has been used:

• as a standard in bradford protein estimation method in yeast cells
• in elispot assay of blood cells
• as a blocking agent in immunohistochemical studies of transplant
• as a blocking agent in western blotting of human gastric cancer cell lines

Certain conformational and primary-sequence epitopes of BSA are suspected allergens in human beef and milk allergies.

Prepared by salt fractionation, ion exchange, and gel filtration chromatography.

Serum albumin may be referred to as Fraction V. This naming convention is taken from the original Cohn method of fractionating serum proteins using cold ethanol precipitation. Serum albumin was found in the fifth ethanol fraction using Cohn′s method. Since then, the term "Fraction V" has been used by some to describe serum albumin regardless of the method of preparation. Others have used this term to describe serum albumin purified by ethanol fractionation methods that have been highly modified since the original Cohn method was described. Sigma-Aldrich manufactures and distributes serum albumins purified from a variety of primary methods including the true Cohn fractionation method, modified ethanol fractionation methods, heat shock and chromatography. Additional purification steps may include crystallization or charcoal filtration.