A7030 Sigma-Aldrich

Bovine Serum Albumin

heat shock fraction, protease free, fatty acid free, essentially globulin free, pH 7, ≥98%

Synonym: Albumin bovine serum, BSA, Bovine albumin



Related Categories Albumin, Biochemicals and Reagents, Bovine Serum Albumins, Heat Shock Fractionated, Proteins and Derivatives More...
Quality Level   200
biological source   bovine
assay   ≥98%
form   lyophilized powder
mol wt   ~66 kDa
purified by   heat shock fractionation
origin   USA origin
free fatty acid content   ≤0.02%
application(s)   ELISA: suitable
  blood typing: suitable
  ligand binding assay: suitable
impurities   essentially globulin free
loss   ≤5%
pH   7
solubility   water: soluble (40 mg/ml)
foreign activity   protease ≤0.005 U/mg
storage temp.   2-8°C
Gene Information   bovine ... ALB(280717)


General description

Bovine serum albumin is a protein which has a key role in regulating blood colloidal osmotic pressure. A water-soluble protein composed of 583 amino acids, BSA has a calculated molecular weight of 66,430 Daltons. Six α-helices form three homologous domains of BSA. Depending on pH, BSA undergoes reversible conformational isomerization. The native structure of the protein becomes reactive and flexible on heating.

This BSA product is specifically evaluated and tested for the following properties:
• Very low protease content / protease-free
• Very low fatty acid content / fatty acid-free

Protease-free BSA is especially useful for 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:
• as a constituent of medium used for the differentiation of human pluripotent stem cells
• in enzyme-linked immunosorbent assay (ELISA) and sandwich ELISA
• to permeabilize fetal cortical cells

This A7030 BSA has specifically been used as a component of blocking buffer in a peptide-based ELISA assay for analysis of COVID-19 / SARS-CoV-2 samples (Poh, C.K. et al., Nat. Commun., 11(1), 2806 (2020)).


1 kg in poly bottle

10, 50, 100, 500 g in poly bottle

5 kg in poly drum

Biochem/physiol Actions

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

Features and Benefits

• Heat shock fractionated
• Protease-free
• Fatty acid-free
• Essentially globulin-free

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.

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable

Frequently Asked Questions

What is the molecular weight of A7030, BSA?
Albumin has a molecular weight of 66,430 g/mol as a single polypeptide chain.
Is Product No. A7030, BSA fraction V?
All albumins are fraction V. Based on the fractionation of serum, fraction I is fibrinogen, fraction II is gamma-globulins, fraction III is beta-globulins, fraction IV is alpha-globulins, and fraction V is albumin.
What does "fatty acid free" mean as it relates to BSA albumin, Product A7030?
Albumin has 4 hydrophobic binding domains but the normal load is 1 to 2 molecules per molecule of albumin. The normal level of fatty acids for albumin is 0.05 % +/- 0.03 %. Fatty acid free albumin will have less than 0.005 % fatty acids.
How many lysine residues does A7030 albumin have?
Bovine albumin will have 59 lysine residues but not all of them are accessible for conjugation.
What is the half life of Product A7030, BSA albumin in the circulation?
The normal half-life of circulating albumin is 19 days.
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.
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.
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.
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.
My question is not addressed here, how can I contact Technical Service for assistance?
Ask a Scientist here.
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Protocols & Articles
Peer-Reviewed Papers


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