Bovine serum albumin (BSA)

Molecular Classification

Globular protein, plasma carrier protein, serum albumin protein family

Other Names

Fraction V, Albumin bovine, BSAV, AlbuMin Bovine V, Serum albumin (bovine), Bovine SeruM AlbuMin solution

Disease Roles

Allergenicity in food and serum preparationsUsed clinically for plasma volume expansion (not as a disease target, but as a therapeutic agent for hypovolemia)

Bovine serum albumin Overview

Bovine serum albumin is a monomeric, water-soluble plasma protein made up of a single chain of 583 amino acids, with a molecular weight of approximately 66.5 kDa. It consists of three homologous domains (I, II, III), each divided into two subdomains, forming a heart-shaped molecule primarily composed of α-helices. BSA binds a wide variety of small molecules including fatty acids, hormones, bilirubin, and drugs, and is essential for maintaining oncotic pressure and stabilizing extracellular fluid volume in bovine blood. It is highly soluble, stable, and widely used as a protein standard, stabilizer, and carrier in research and industrial applications. While allergenic, BSA is generally considered to be non-toxic and non-antigenic in laboratory use, with its structure well-resolved by crystallography. It is not a drug target, but its ligand-binding properties make it valuable for studying drug-protein interactions and pharmacokinetics.

Mechanism of Action

Non-specific binding of ligands via hydrophobic and electrostatic interactions. Uptake and transport of bound small molecules and drugs.

Biological Functions

Maintenance of oncotic pressure

Carrier of fatty acids, hormones, bilirubin, minerals, and drugs

Antioxidant

Stabilization of extracellular fluid volume

Disease Associations

Allergenicity in food and serum preparations

Used clinically for plasma volume expansion (not as a disease target, but as a therapeutic agent for hypovolemia)

Safety Considerations

Allergenicity risk in some individuals, especially with repeated exposure or in parenteral preparations
Potential contamination in preparations leading to false results in laboratory assays

Interacting Drugs

Salicylate

Sulfonamides

Bilirubin

Thyroxine

Tryptophan

Octanoate

Various aromatic drugs and metabolites (BSA is often used for drug-binding studies and as a stabilizer)