Albumin, Bovine from Bovine Serum

Albumins are a group of acidic proteins which occur in the body fluids and tissues of mammals and in some plant seeds. Serum and plasma albumin is carbohydrate free and comprises 55-62% of the protein present. Bovine albumin is a single polypeptide chain consisting of approximately 583 to 595 amino acid residues and no carbohydrates. At pH 5-7 it contains 17 intra-chain disulfide bridges and 1 sulfhydryl group. Additional removal of impurities can be accomplished by crystallization, preparative electrophoresis, ion exchange chromatography, affinity chromatography (e.g., ConA-agarose removes glycoproteins), heat treatment (removes globulins), low pH treatment, charcoal treatment, organic solvent precipitation (i.e. isooctane) and low temperature treatment. Charcoal treatment and organic solvent precipitation remove fatty acids.

Certain conformational and primary-sequence epitopes of BSA are suspected allergens in human beef and milk allergies. Albumin binds water, Ca2+, Na+ and K+. Due to a hydrophobic cleft, albumin binds fatty acids, bilirubin, hormones and drugs. The main biological function of albumin is to regulate the colloidal osmotic pressure of blood and to a lesser degree to provide cellular nutrition. Human and bovine albumins contain 16% nitrogen and are often used as standards in protein calibration studies.