Bovine serum albumin (BSA) is a non-glycosylated protein belonging to the serum albumins family. It is a globular protein with α-helix structure and 17-disulfide bonds. BSA has a molecular weight of 66 kDa consisting three domains and two subdomains under each. BSA shows structural similarity with human serum albumin.

BSA is widely used as a blocking agent in immunoassays and immunodetection procedures, and also as a carrier protein for dilution of antibodies. Thus it is of concern to be aware of potential trace endogenous content of globulins / IgG in BSA, because of concerns that such trace globulins / IgG may serve as antigens for secondary antibodies in immunodetection work. This product undergoes testing for low IgG content / status as essentially immunoglobulin-free.

Select the right albumin for your application with the Albumin Selection Guide

BSA is widely used as a blocking agent in immunoassays and immunodetection procedures, and also as a carrier protein for dilution of antibodies. Thus it is of concern to be aware of potential trace endogenous content of globulins / IgG in BSA, because of concerns that such trace globulins / IgG may serve as antigens for secondary antibodies in immunodetection work. This product undergoes testing for low IgG content / status as essentially immunoglobulin-free.

Select the right albumin for your application with the Albumin Selection Guide.

Bovine Serum Albumin has been used to treat polyomavirus BK to serve as a control in testing intravenous immunoglobulins preparations.

Bovine Serum Albumin (BSA) acts as a carrier protein for drugs, hormones and fatty acids. It is an essential component of cell culture medium. BSA serves as a blocking agent in enzyme linked immunosorbent assay (ELISA) and prevents non-specific binding of antigens and antibodies to the microtiter plates. Due to its high solubility, low cost and purity and interaction with surfactant, it is useful in pharmaceutical and cosmetic industry.

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

Prepared by salt fractionation, ion exchange, and gel filtration chromatography.

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.