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Bovine Serum Albumin

heat shock fraction, pH 7, ≥98%

Albumin bovine serum, Bovine albumin, BSA
CAS Number:
EC Number:
MDL number:

biological source





lyophilized powder

mol wt

~66 kDa

purified by

heat shock fractionation


USA origin


immunocytochemistry: suitable






water: soluble (40 mg/ml)

UniProt accession no.

storage temp.


Gene Information

bovine ... ALB(280717)

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General description

Bovine serum albumin is a protein whose key biological function is to regulate the colloidal osmotic pressure of blood. BSA is widely used in various studies and applications. Made up of 583 amino acids, BSA is a water-soluble protein with a calculated molecular weight of 66,430 Da. Six α-helices form three homologous domains of BSA. Depending on pH, it undergoes reversible conformational isomerization. The native structure of the protein becomes reactive and flexible on heating.


Bovine Serum Albumin is used for many applications, including the following applications:
  • BSA has been used in cell culture, e.g. as a supplement in media prepared for culturing of oligodendrocytes.
  • BSA has been used for the dilution of primary antibody solution in immunohistochemistry procedures.
  • BSA has been used as a standard in the Bradford method of protein quantification.
  • BSA has been used in blocking and permeabilization buffer for immunofluorescence studies.


10, 50, 100, 500 g in poly bottle
1 kg in poly bottle

Biochem/physiol Actions

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

Preparation Note

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.

Storage Class Code

11 - Combustible Solids



Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

Product Information Sheet

Quotes and Ordering

  1. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  2. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  3. What is the molecular weight of Product A9647, Albumin from bovine serum?

    The molecular weight of BSA is 66,430.

  4. How can the concentration of a solution of Product A9647, Albumin from bovine serum, be quantified?

    The concentration of a solution of BSA can be measured by using the extinction coefficient (E1%) of 6.67. The 1% refers to a solution that is 1% weight-to-volume (i.e., 10 mg/mL).

  5. What is the pH of a solution of Product A9647, Albumin from bovine serum?

    The pH of a 1% solution is approximately 7.0, according to the product specifications.

  6. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  7. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  8. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

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Colorimetric Detection of Western blot using 4-Chloro-1-Naphthol Solution Protocol

Solution contains 0.48 mM 4-Chloro-1-Naphthol, 50 mM Tris-HCl and 0.2 M NaCl in 17% methanol. This is a substrate solution designed for visualizing horseradish peroxidase conjugates in Western Blotting.

Fast Analysis of Monoclonal Antibodies Using Silica Monoliths Designed for Bioanalysis

Silica monoliths with larger mesopores are a powerful tool for the fast separation of biomolecules including mAbs. The immobilization of protein A on epoxy-modified widepore (WP) silica rods enabled highly reproducible and fast, one minute, separations of mAbs. The Chromolith® WP 300 is also available with a protein A phase.

Albumin in Cell Culture

This page segues to comprehensive insights on how serum albumin and other important cell culture components affect the performance of serum-free cell culture systems used for biomanufacturing heterologous proteins including monoclonal antibodies. The page introduces the in vitro chemistry and biochemistry of albumin. These insights may also be applied to ex vivo and tissue engineering applications.


Enzymatic Assay of Alcohol Dehydrogenase (EC

This procedure may be used for Alcohol Dehydrogenase products.

Immunohistochemistry Procedure

Use this protocol to for the entire immunohistochemistry (IHC) procedure through staining and visualization of specific antigens in paraffin-embedded tissue sections.

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