Bovine serum albumin

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Serum albumin
Serum albumin
according to PDB  3V03
other names

BSA, Allergen Bos d 6

Existing structure data : PDB  2L7U , PDB  4F5S

Mass / length primary structure 583 amino acids , 66,463 Da
Precursor 607 amino acids , 69,293 Da
Identifier
External IDs
Orthologue
Beef human
Entrez 280717 213
Ensemble ENSBTAG00000017121
UniProt P02769 P02768
Refseq (mRNA) NM_180992.2
Refseq (protein) NP_851335.1
Gene locus
PubMed search 280717 213

Bovine serum albumin (BSA, synonymous with bovine serum albumin ) is a protein from the blood serum of domestic cattle ( Bos taurus ). Because of its low cost, it is used for various purposes in biochemistry when any pure protein is required.

properties

lyophilized bovine serum albumin

Bovine serum albumin occurs mainly in the blood plasma of cattle , where it is the most abundant protein. It has a high binding capacity for polar substances such as water , Ca 2+ , Na + , K + , as well as for less polar substances such as fatty acids , hormones , bilirubin and various drugs . Its main function is the regulation of colloid osmotic pressure in the blood . It is also the main transport protein for zinc ions and binds about 80% of the Zn 2+ in the blood plasma. BSA has one binding site for Cu 2+ at position 27 and four binding sites for Zn 2+ at positions 91, 123, 270 and 272. After translation it undergoes various post-translational modifications such as proteolysis of the signal peptide (position 1-18), proteolysis behind two basic amino acids at position 24, methylations and phosphorylations . In addition, BSA has disulfide bridges . BSA has been described as the Bos d6 allergen and is found in beef and cow's milk .

The homology of BSA to human serum albumin is only 75.8% at the amino acid level. The isoelectric point at 25 ° C is pH 4.7. The pH value of a one percent solution of BSA is between 5.2 and 7. The isoionic point (pH value of BSA without ions) is pH 5.2. The dimensions are approximately 140  Å × 40 Å × 40 Å, the Stokes radius is 34.8 Å. The extinction coefficient at a wavelength of 279 nm is 43.824 M −1 cm −1 . The rotation value [α] 259 is -61 ° and for [α] 264 -63 °. The sedimentation coefficient of BSA S 20, W is 4.5 × 10 −13 s for the monomer and 6.7 × 10 −13 s for the dimer. The diffusion constant D 20, W is 5.9 × 10 −7  cm 2 / s. The partial specific volume V 20 is 0.000733 m 3 kg −1 . The intrinsic viscosity is η = 4.13 cm³ / g at pH 5.13. The extinction A 279 nm 1 g / L is 0.667. The helical proportion of BSA is 54% and the leaflet proportion 18%. MOPS can increase the thermostability of bovine serum albumin in solutions.

A peptide of the BSA in positions 165 to 173 has been described as a neurotensin-related peptide (NRP) and erroneously described as being involved in the regulation of the digestion of fats , the uptake of lipids and the blood flow.

use

Commercially purified BSA is also referred to as fraction V , named after the fraction in the Cohn extraction after Edwin J. Cohn . It is used in standard series to determine protein concentration , e.g. B. Bradford test , Lowry test , biuret reaction and BCA test . In the SDS-PAGE , BSA is used as the comigration standard . In the polymerase chain reaction , it is used to bind inhibitors .

When Western blot , the ELISA , the ELISpot , in immunohistochemistry , and generally in immunostaining in immunoassays it is used as part of the blocking solution. As a result, non-specific protein-binding areas are saturated with BSA, which reduces the adsorption of other, more expensive proteins on the surfaces of the reaction vessels used or on blot membranes . BSA is also used in the hybridization of nucleic acids in Denhardt's solution to block unspecific binding sites for proteins and nucleic acids ; it is used accordingly in Southern blot and Northern blot . BSA is also added to some restriction enzymes . However, it is less helpful in avoiding protein adsorption than 0.2 mM octoxinol 9 (synonym Triton X-100 and Nonidet P40), or solutions of 3% (m / V) polyvinylpyrrolidone -40 with a mild detergent such as 0, 05% (m / V) Tween 20 .

literature

Web links

Individual evidence

  1. ↑ a b c d e f g h i ALB - Serum albumin precursor - Bos taurus (Bovine) - ALB gene & protein. In: uniprot.org. June 20, 2018, accessed June 21, 2018 .
  2. ↑ P. Restani, C. Ballabio, A. Cattaneo, P. Isoardi, L. Terracciano, A. Fiocchi: Characterization of bovine serum albumin epitopes and their role in allergic reactions. In: Allergy. Volume 59 Suppl 78, August 2004, pp. 21-24, doi : 10.1111 / j.1398-9995.2004.00568.x , PMID 15245352 .
  3. ↑ A. Bujacz: Structures of bovine, equine and leporine serum albumin. In: Acta crystallographica. Section D, Biological crystallography. Volume 68, Pt 10 October 2012, pp. 1278-1289, doi : 10.1107 / S0907444912027047 , PMID 22993082 .
  4. ↑ S. Ge, K. Kojio, A. Takahara, T. Kajiyama: Bovine serum albumin adsorption onto immobilized organotrichlorosilane surface: influence of the phase separation on protein adsorption patterns. In: Journal of biomaterials science. Polymer edition. Volume 9, Number 2, 1998, pp. 131-150, PMID 9493841 .
  5. ↑ a b c d e f F. W. Putnam: The Plasma Proteins: Structure, Function and Genetic Control. Volume 1, 2nd edition, Academic Press, 1975. ISBN 0-12-568401-0 . Pp. 141, 147, 151.
  6. ^ AK Wright, MR Thompson: Hydrodynamic structure of bovine serum albumin determined by transient electric birefringence. In: Biophysical Journal . Volume 15, Number 2 Pt 1, February 1975, pp. 137-141, PMID 1167468 , PMC 1334600 (free full text).
  7. ↑ a b P. G. Squire, P. Moser, CT O'Konski: The hydrodynamic properties of bovine serum albumin monomer and dimer. In: Biochemistry. Volume 7, Number 12, December 1968, pp. 4261-4272, PMID 5750167 .
  8. ^ Inge Axelsson: Characterization of proteins and other macromolecules by agarose gel chromatography. In: Journal of Chromatography A. 152, 1978, pp. 21-32, doi : 10.1016 / S0021-9673 (00) 85330-3 .
  9. ^ Myron L. Wagner, Harold Scheraga: Gouy Diffusion Studies of Bovine Serum Albumin. In: The Journal of Physical Chemistry. 60, 1956, pp. 1066-1076, doi : 10.1021 / j150542a012 .
  10. ↑ Margaret J. Hunter: A Method for the Determination of Protein Partial Specific Volumes. In: The Journal of Physical Chemistry. 70, 1966, pp. 3285-3292, doi : 10.1021 / j100882a043 .
  11. ↑ George I. Loeb, Harold A. Scheraga: Hydrodynamic and Thermodynamic Properties of Bovine Serum Albumin at Low pH. In: The Journal of Physical Chemistry. 60, 1956, pp. 1633-1644, doi : 10.1021 / j150546a009 .
  12. ↑ EJ Cohn, WL Hughes, JH Weare: Preparation and properties of serum and plasma proteins; crystallization of serum albumins from ethanol water mixtures. In: Journal of the American Chemical Society . Volume 69, Number 7, July 1947, pp. 1753-1761, PMID 20251413 .
  13. ^ BS Gupta, M. Taha, MJ Lee: Buffers more than buffering agent: introducing a new class of stabilizers for the protein BSA. In: Physical chemistry chemical physics: PCCP. Volume 17, Number 2, January 2015, pp. 1114–1133, doi: 10.1039 / c4cp04663c . PMID 25415385 .
  14. ↑ CA Kreader: Relief of amplification inhibition in PCR with bovine serum albumin or T4 gene 32 protein. In: Applied and environmental microbiology. Volume 62, Number 3, March 1996, pp. 1102-1106, PMID 8975603 , PMC 167874 (free full text).
  15. ↑ CH Suelter, M. DeLuca: How to prevent losses of protein by adsorption to glass and plastic. In: Analytical biochemistry. Volume 135, Number 1, November 1983, pp. 112-119, PMID 6670734 .
  16. ↑ John W. Haycock: Polyvinylpyrrolidone as a blocking agent in immunochemical studies. In: Analytical Biochemistry. Vol. 208, No. 2, 1993, pp. 397-399, PMID 8095775 , doi : 10.1006 / abio.1993.1068 .
  17. ↑ Klaus Klarskov, Stephen Naylor: India ink staining after sodium dodecyl sulfate polyacrylamide gel electrophoresis and in conjunction with Western blots for peptide mapping by matrix-assisted laser desorption / ionization time-of-flight mass spectrometry. In: Rapid Communications in Mass Spectrometry. Vol. 16, No. 1, 2002, ISSN  0951-4198 , pp. 35-42, PMID 11754245 , doi : 10.1002 / rcm.522 .