Bovine Serum Albumin

Bovine serum albumin (BSA), a 66 kDa protein, belongs to the family of serum albumins. It is an α-helical, non-glycosylated and globular protein, that has 17-disulfide bonds.

Bovine Serum Albumin has been used:

• as a component of cell culture media in cochlear explant culture
• organotypic cultures and embryo culture
• as a component of phosphate-buffered saline (PBS) in immunostaining of human induced pluripotent stem cell (hiPSC)

Bovine Serum Albumin (BSA) is the most vital constituent of the cell culture media, which aids embryonic stem cells (hESC) differentiation. It acts as a blocking agent in enzyme linked immunosorbent assay (ELISA) to inhibit non-specific binding of antigens and antibodies to the microtiter plates.

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

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.