Bovine Serum Albumin

Bovine serum albumin (BSA) has an important role in the regulation of blood colloidal osmotic pressure. BSA is the major protein in bovine serum, and is composed of 583 amino acids with a calculated molecular weight of 66,430 Daltons. BSA is used in many different applications and fields, such as:

• Protein quantitation (as a standard)
• Immunochemistry (as a blocking agent)
• Cell culture (as a nutrient)

This particular BSA is specifically evaluated and tested to have very low protease content / for protease-free status. Protease-free BSA may be used in applications like:

• Enzyme assays
• Protein-based assays
• Protease-sensitive techniques that include:

a) Enzyme immunoassay (EIA)
b) Nucleic acid hybridization
c) Radioimmunoassay (RIA)

Bovine Serum Albumin has been used in luminescence assays.

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.