Bovine Serum Albumin

Bovine serum albumin (BSA) is 66 kDa protein consisting of three domains with two subdomains under each. It is α-helical globular and a non-glycosylated protein.

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.

Bovine Serum Albumin has been used:

• as a blocking agent in enzyme linked immunosorbent assay (ELISA)(154)
• as a component of Dulbecco PBS medium for preantral follicles culture(155)
• as a component of modified Tris-buffered medium (mTBM) for oocyte insemination(156)

Bovine Serum Albumin (BSA) is a transporter for drugs, hormones and fatty acids. It is a blocking agent used in enzyme linked immunosorbent assay (ELISA) for preventing non-specific binding of antigens and antibodies to the microtiter plates. The cysteine and tyrosine residues of BSA have high affinity for metal binding.

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

May yield an insulin blank of up to 0.1 μunit per mg in certain procedures.