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