Albumins are simple water-soluble proteins found in animal fluids and tissues and to a lesser extent plants. Many molecules are unstable or insoluble when they exist in non-complexed forms. In vitro, albumin is used to bind, sequester and stabilize a range of important small molecules and proteins. We offer a wide variety of albumins including bovine serum albumins (BSA), human serums, and albumin solutions for your research and manufacturing needs.

Serum albumin may be referred to as Cohn 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 "Cohn 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.

Cohn, E.J., et al. J. Am. Chem. Soc., 68, 459, (1946)