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Bovine serum albumin, Bovine Albumin, BSA, also known as "Fraction V", is a serum albumin protein that has numerous biochemical applications including ELISAs (Enzyme-Linked Immunosorbent Assay), blots, and immunohistochemistry. It is also used as a nutrient in cell and microbial culture. In restriction digests, BSA is used to stabilize some enzymes during digestion of DNA and to prevent adhesion of the enzyme to reaction tubes and other vessels. This protein does not affect other enzymes that do not need it for stabilization. BSA is used because of its stability, its lack of effect in many biochemical reactions, and its low cost since large quantities of it can be readily purified from bovine blood, a byproduct of the cattle industry.
The nickname "Fraction V" refers to albumin being the fifth fraction of the original Edwin Cohn purification methodology that made use of differential solubility characteristics of plasma proteins. By manipulating solvent concentrations, pH, salt levels, and temperature, Cohn was able to pull out successive "fractions" of blood plasma. The process was first commercialized with human albumin for medical use and later adopted for production of BSA.
[edit] Physical properties
- Number of residues: 583
- Molecular Weight: 66.430 kDa
- pI in Water at 25 ℃: 4.7
- Extinction Coefficient: 0.667 ml mg-1 cm-1[1][1]
A 18-residue signal peptide is cut off from the precursor protein upon secretion, hence the precursor has 607 amino acid residues and a molecular weight of ca. 69.4 kDa.
[edit] References
IVD Technology Article
[edit] See also
[edit] External links
