Bovine Serum Albumin

Bovine serum albumin (BSA) is a 66 kDa protein consisting of three domains with two subdomains under each. It is a α-helical, globular and non-glycosylated protein. BSA belongs to the serum albumins family. It has 17-disulfide bonds.

Bovine Serum Albumin has been used in:

• the washing of the rabbit tissue sections in immunofluorescence microscopy
• incubation of red blood cells (RBC) for flow cytometry analysis
• as a component of Hanks′ balanced salt solution with Ca²⁺ and Mg²⁺ (HBSS++) for eosin-5-maleimide staining and RBC washing in magnetic circular dichroism measurements

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

Bovine Serum Albumin (BSA) is a transporter for drugs, hormones and fatty acids. It is used as a blocking agent in enzyme linked immunosorbent assay (ELISA) for preventing non-specific binding of antigens and antibodies to the microtiter plates. It is a crucial component of the cell culture media and favors embryonic stem cells (hESC) differentiation. BSA shares structural features with human serum albumin. Its high solubility, low cost and purity and interaction with surfactant is exploited in cosmetic and pharmaceutical industry.

Prepared using heat shock fractionation.

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.