Bovine Serum Albumin

Bovine Serum Albumin has been used:

• as a component of blocking solution used for fixing Drosophila embryos in immunostaining
• to block 96-deep-well plates in phage immunoprecipitation studies
• as a standard solution in fluorescence spectroscopy studies

Bovine Serum Albumin (BSA) displays intrinsic fluorescence due to the presence of two tryptophan residues. It is widely used in ligand interaction studies and in the delivery of drugs and antibodies. BSA is used as a blocking agent in enzyme-linked immunosorbent assay (ELISA).

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

Bovine Serum Albumin has three homologous domains (I, II, and III) that are connected by disulfide bonds. BSA shares structural homology with human serum albumin (HSA).

Derived from New Zealand source serum

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.