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Bovine serum albumin

Bovine serum albumin (BSA) is the predominant protein in bovine blood serum, accounting for 55-62% of the total serum protein content.^[1] It is a water-soluble, monomeric protein with a molecular weight of 66,430 Da, consisting of a single chain of 583 amino acids.^[1] BSA exhibits a heart-shaped, globular structure comprising three homologous domains (I, II, III), each with two subdomains (A and B), and is stabilized by 17 intrachain disulfide bridges and one free sulfhydryl group.^[2] Approximately 74% of its secondary structure is α-helical, with the remainder consisting of turns and flexible loops.^[2] In its biological role, BSA primarily maintains the colloidal osmotic pressure of blood, which helps regulate fluid balance between the vascular system and tissues.^[1] It also acts as a versatile carrier, binding and transporting a diverse array of endogenous and exogenous ligands, including fatty acids, bilirubin, hormones, metal ions such as Ca²⁺ and Mg²⁺, and pharmaceuticals, thereby influencing their solubility, distribution, and bioavailability in circulation.^[2] Additional functions include contributing to blood pH buffering and preventing the aggregation of other proteins.^[2] The protein's isoelectric point ranges from 4.7 to 5.3, depending on fatty acid content, which affects its solubility and binding behavior at physiological pH.^[1] BSA's stability, low cost, and non-toxicity make it a staple in laboratory and industrial applications. It is commonly employed as a protein standard in quantification assays like the Bradford method due to its well-characterized properties. In immunoassays and Western blotting, BSA serves as a blocking agent to minimize non-specific binding and background noise.^[1] Furthermore, it is added to cell culture media as a supplement to stabilize enzymes, protect cells from oxidative damage, and enhance growth.^[3] Purified BSA is commercially available in various grades, often derived from bovine plasma through heat shock fractionation or other purification techniques.

Introduction

Definition and Biological Origin

Bovine serum albumin (BSA) is the most abundant protein in the blood plasma of cows (Bos taurus), accounting for 55-62% of the total serum protein content.^[1] As a member of the albumin family, it is a soluble, monomeric globular protein with a molecular weight of approximately 66,430 Da and an empirical molecular formula of C₅₉₇₉H₉₅₉₀N₁₆₅₀O₁₈₈₉S₄₀.^[4] Synthesized primarily in the liver, BSA circulates in the bloodstream and contributes to the maintenance of colloidal osmotic pressure, which helps regulate fluid balance between the vascular system and tissues in bovine physiology.^[5] BSA is derived from the serum fraction of bovine blood, which is collected as a byproduct from healthy, slaughtered cows during meat processing at slaughterhouses.^[6] The blood is fractionated using methods such as cold ethanol precipitation to isolate the albumin-rich fraction, ensuring the protein remains non-glycosylated and functional as in its native state.^[7] This process leverages waste materials from the livestock industry, making BSA a readily available biomolecule while adhering to regulatory standards for animal-derived products.^[8] Evolutionarily, BSA is part of a conserved albumin superfamily that originated in early vertebrates and has been maintained across mammalian lineages through structural and functional adaptations.^[9] Homologs in other mammals, such as human serum albumin, share high sequence similarity and perform analogous roles in plasma transport and osmotic regulation, reflecting the protein family's ancient divergence from ancestral precursors.^[10]

Historical Development

Bovine serum albumin (BSA) emerged from early studies on blood proteins, with albumins recognized as water-soluble components comprising roughly half of plasma in the 19th century. By 1894, albumin was established as a distinct entity, and in 1926, its molecular weight was determined to be about 70,000 daltons, marking foundational progress in understanding serum proteins.^[11] Significant advancements occurred during World War II amid urgent needs for blood plasma substitutes. In late 1940, biochemist Edwin J. Cohn and his team at Harvard Medical School developed the cold ethanol fractionation process, a method using varying ethanol concentrations, low temperatures, and pH adjustments to isolate albumin from plasma efficiently. This technique, initially applied to human plasma, proved vital for producing stable protein solutions to treat shock and hemorrhage in military settings.^[12]^[13] Clinical evaluation of bovine-derived albumin began in April 1941 under U.S. Army auspices, involving intravenous infusions in over 200 human subjects, including volunteers and patients with blood loss. Testing, which continued for nearly two years, confirmed BSA's low viscosity, osmotic stability, and functional similarity to human albumin as a plasma expander, though rare adverse reactions like serum sickness were noted, ultimately halting its clinical use for humans by 1943.^[14]^[15] Following the war, BSA production shifted emphasis to bovine sources for commercialization starting in 1945, driven by the greater availability and reduced cost of cattle blood compared to human donations. This transition positioned BSA as a practical biomaterial beyond therapeutics, supporting expanding biochemical research. Lyophilization techniques, refined during wartime efforts, were standardized in the 1950s to yield powdered BSA with extended shelf life, solidifying its role as a laboratory staple.^[11]^[15] The 1990s outbreak of bovine spongiform encephalopathy (BSE) raised safety concerns for bovine-derived products, leading to post-2000 regulatory enhancements in production, including sourcing from low-risk regions and rigorous prion testing to prevent contamination in biologics. In response, 2023 research demonstrated viable recombinant BSA produced via fungal expression systems, achieving structural equivalence to native forms and enabling animal-free manufacturing for sensitive applications.^[16]^[17]^[18]

Structure

Primary Sequence

Bovine serum albumin (BSA) consists of a single polypeptide chain of 583 amino acid residues, derived from the precursor protein through cleavage of an N-terminal signal peptide and propeptide. The amino acid composition features approximately 40% non-polar residues, 20% polar uncharged residues, 14% acidic residues, and 17% basic residues, contributing to its overall hydrophobicity and solubility properties. This composition results in a calculated molecular weight of 66,430 Da based on the sequence.^[4] BSA is encoded by the ALB gene located on bovine chromosome 6. The complete primary sequence was first determined in the 1970s through sequential Edman degradation of peptides generated by enzymatic and chemical cleavage, with later confirmation via cDNA sequencing and genomic analysis.^[19] The sequence includes 35 cysteine residues, which form 17 intramolecular disulfide bonds stabilizing the chain, leaving one free thiol group at position Cys34 with no other free cysteines. Post-translational modifications are minimal but include a potential N-linked glycosylation site at Asn494, though commercial BSA is typically non-glycosylated.^[20]^[4] BSA exhibits 76% sequence identity with human serum albumin (HSA), including conserved cysteine positions for disulfide formation but with variations in residues that affect thermal stability and ligand interactions.^[21]

Three-Dimensional Structure

Bovine serum albumin (BSA) adopts a compact, heart-shaped monomeric structure that folds from its 583-amino-acid polypeptide chain into three homologous domains (I, II, and III), each further subdivided into A and B subdomains. This globular architecture is predominantly α-helical, featuring nine major α-helices distributed across the domains and short β-turns with minimal β-sheet content, contributing to the overall stability and ligand-binding pockets. The molecule's dimensions are approximately 4 nm × 4 nm × 14 nm, reflecting its asymmetric yet rigid form suitable for transport functions in blood plasma. Secondary structure estimates vary by method, with ~67% α-helical by common spectroscopic analyses. The structure is rigidly maintained by 17 intramolecular disulfide bridges, which create a scaffold of nine double loops arranged in repeating triplets, preventing unfolding under physiological conditions and ensuring monomeric behavior without quaternary associations.^[22] These cystine linkages, conserved across serum albumins, link specific cysteine residues (e.g., Cys90–Cys101 in domain I) and distribute evenly to reinforce subdomain interfaces.^[22] X-ray crystallography has provided high-resolution insights into this fold, with the first BSA structure solved at 2.47 Å resolution (PDB: 4F5S) revealing the precise helical packing and minimal β-sheet content, confirming its ~67% α-helical composition.^[22] BSA's conformation varies with pH, transitioning from the normal (N) form at pH 7—characterized by a tightly packed, native globular state—to the fast (F) form at pH 4, where partial unfolding exposes hydrophobic regions without full expansion, and the expanded (E) form at pH 3, marked by significant elongation and loss of compactness due to electrostatic repulsion near the isoelectric point. These pH-dependent states, first described through electrophoretic mobility studies and later corroborated by scattering techniques, highlight the protein's adaptability while preserving its monomeric integrity under physiological pH ranges. Subsequent structures (e.g., PDB: 3V03 at 2.70 Å) from the 2010s have refined these models, emphasizing the role of domain flexibility in conformational shifts.

Properties

Physicochemical Characteristics

Bovine serum albumin (BSA) possesses distinct physicochemical properties that underpin its stability and functionality in aqueous environments. Its isoelectric point (pI) ranges from 4.7 to 5.3, depending on fatty acid content, which results in a net negative charge at physiological pH levels (typically 7.4), classifying it as anionic under these conditions.^[1] This charge profile influences BSA's interactions in solution and its separation via electrophoretic or chromatographic methods. BSA exhibits exceptional solubility in water, surpassing 40 mg/mL at 20°C, enabling high-concentration preparations without precipitation. The protein remains heat-stable up to 60°C, preserving its native conformation, though thermal denaturation initiates around 65°C, as observed through calorimetric analysis.^[23] These thermal traits, linked to its compact globular structure, allow BSA to withstand moderate processing conditions in laboratory applications. For spectroscopic characterization, BSA shows maximum UV absorbance at 279 nm, with an extinction coefficient yielding an A₂₈₀ value of 0.66 for a 1 mg/mL solution in a 1 cm pathlength cuvette. In light scattering experiments, its refractive index increment is 0.190 mL/g, facilitating accurate molecular weight determinations. The diffusion coefficient in water at 20°C (D_20,w) measures 5.9 × 10^-7 cm²/s, indicating moderate mobility consistent with its size and shape. Laboratory-grade BSA is standardized to ≥98% purity, verified by SDS-PAGE to confirm the ~66 kDa monomeric band and by HPLC to quantify contaminants such as globulins or fatty acids.

Ligand Binding

Bovine serum albumin (BSA) exhibits a remarkable capacity to bind long-chain fatty acids at multiple sites, with seven high-affinity binding sites primarily located in subdomains IIA and IIIA.^[24] These sites enable BSA to accommodate up to 11-17 fatty acid molecules, though binding affinity decreases progressively with occupancy.^[25] The dissociation constants (Kd) for these high-affinity interactions typically range from 10^{-6} to 10^{-8} M, reflecting strong non-covalent associations driven by hydrophobic and electrostatic forces.^[24] In addition to fatty acids, BSA possesses two principal drug-binding pockets known as Sudlow sites I and II. Sudlow site I, situated in subdomain IIA, preferentially binds warfarin and other aromatic carboxylic drugs, while Sudlow site II in subdomain IIIA accommodates digitoxin and ibuprofen.^[26] Bilirubin also interacts specifically at Sudlow site I with a 1:1 stoichiometry, forming a tight complex that stabilizes the ligand through hydrogen bonding and van der Waals interactions.^[27] Ligand binding to BSA is often modeled using the Langmuir isotherm equation to describe saturation behavior:

\theta = \frac{K [L]}{1 + K [L]}

where \theta represents the fraction of occupied binding sites, K is the association constant (inverse of Kd), and [L] is the ligand concentration; this model assumes independent, identical sites and no cooperativity.^[28] Dissociation constants are commonly determined via fluorescence quenching assays, which monitor changes in the intrinsic fluorescence of BSA's tryptophan residues, Trp134 (in subdomain IB, more solvent-exposed) and Trp213 (in subdomain IIA, buried in a hydrophobic environment).^[29] Ligand binding quenches this emission, with the extent of quenching proportional to binding affinity, allowing quantitative Kd estimation through Stern-Volmer analysis.^[29] Compared to human serum albumin (HSA), which contains only one tryptophan residue (Trp214 in subdomain IIA), BSA's two tryptophan residues confer greater fluorescence sensitivity in binding studies, as both can contribute to quenching signals and reveal nuanced conformational changes upon ligand association.^[30]

Biological Functions

Transport in Blood

Bovine serum albumin (BSA) plays a pivotal role in maintaining the colloidal oncotic pressure within bovine capillaries, contributing approximately 80% of the total plasma osmotic pressure due to its abundance and molecular properties. This oncotic pressure counteracts hydrostatic forces, preventing excessive fluid extravasation from the vascular compartment into interstitial spaces and thereby supporting fluid balance in circulation.^[31]^[32] As a key transport protein in bovine blood, BSA facilitates the shuttling of non-esterified fatty acids (NEFA) from adipose tissue to metabolically active sites such as the liver and muscles, binding up to several moles of fatty acids per mole of protein through hydrophobic interactions. It also binds and transports hormones, including thyroxine (T4) and various steroids, ensuring their solubility and delivery to target tissues while modulating their bioavailability. Additionally, BSA delivers bilirubin, a byproduct of heme breakdown, from peripheral sites to the liver for conjugation and excretion, preventing toxic accumulation by sequestering it in its high-affinity binding sites.^[33]^[34]^[35] In bovine serum, BSA is present at concentrations of 30-40 mg/mL, representing 55–62% of total serum proteins and enabling its multifunctional roles. Its circulatory half-life is approximately 19 days, prolonged by receptor-mediated endocytosis involving the neonatal Fc receptor (FcRn), which recycles BSA and protects it from lysosomal degradation in endothelial cells.^[20]^[36]^[37]^[38]

Other Physiological Roles

Bovine serum albumin (BSA) exhibits antioxidant activity primarily through its ability to scavenge reactive oxygen species, such as hydroxyl radicals, via its free thiol group at cysteine residue 34. This mechanism helps mitigate oxidative stress in bovine plasma by neutralizing free radicals that could damage cellular components. Additionally, BSA binds pro-oxidant metal ions like Cu²⁺ and Fe³⁺ with high affinity, preventing their participation in Fenton-like reactions that generate harmful reactive oxygen species and thereby protecting against oxidative damage in physiological conditions.^[39]^[40] BSA contributes to anticoagulant effects by binding antithrombin, which enhances the neutralization of thrombin and thereby inhibits fibrin formation in whole blood. This interaction supports the maintenance of blood fluidity under physiological shear conditions. Furthermore, BSA modulates platelet aggregation by interfering with adhesive interactions on platelet surfaces, reducing the propensity for thrombus formation while helping regulate blood viscosity through its colloidal properties.^[41] In immune modulation, BSA binds various bacterial toxins, such as streptolysin O produced by pathogens like Streptococcus pyogenes, facilitating their clearance from circulation and limiting tissue damage. This binding aids in the host's defense by sequestering harmful microbial products. BSA also interacts with inflammatory mediators, including cytokines, exerting anti-inflammatory effects by attenuating excessive immune responses and promoting resolution of inflammation in bovine tissues.^[42]^[43] BSA plays a role in fetal and neonatal development through its elevated concentrations in bovine colostrum compared to mature milk, where it supports nutrient delivery and passive immunity transfer to the newborn calf. As a carrier protein, BSA facilitates the uptake of essential macromolecules across the neonatal gut, contributing to early nutritional support and immune priming before the calf's own systems mature.^[44]

Production and Purification

Traditional Extraction Methods

Bovine serum albumin (BSA) is traditionally extracted from blood collected at slaughterhouses, where whole blood is processed to obtain serum through clotting or anticoagulation followed by centrifugation to separate cellular components and fibrinogen. The primary method for initial isolation is the Cohn cold ethanol fractionation process, developed by Edwin J. Cohn and colleagues in the 1940s as an adaptation for large-scale plasma processing during World War II. This technique exploits differences in protein solubility by sequentially adding ethanol (8-40% final concentration) at low temperatures (-3 to -10°C) and controlled pH levels (typically 4.8-7.2), resulting in five fractions; Fraction V, precipitated at pH 4.8-5.2 and 18-40% ethanol, is enriched in albumin, comprising approximately 60% of its protein content.^[45] Further purification of the crude Fraction V involves heat shock treatment at 60-65°C for 10-30 minutes, which denatures and precipitates contaminating globulins due to BSA's relative thermal stability. This is followed by ammonium sulfate precipitation at 40-60% saturation to selectively salt out albumin, and subsequent ion-exchange chromatography using DEAE-Sepharose columns under controlled ionic strength and pH to remove residual impurities like globulins and lipids. These steps yield approximately 20-40 grams of BSA per liter of starting serum, achieving purities exceeding 95% as measured by electrophoresis or spectroscopy.^[46]^[47]^[48] Safety considerations for traditional BSA production intensified in the 1990s following the bovine spongiform encephalopathy (BSE) outbreak, prompting validated prion removal strategies integrated into the process. These include pasteurization at 60°C for 10 hours to inactivate viruses, supplemented by chemical treatments such as solvent-detergent inactivation or nanofiltration, alongside sourcing blood from BSE-free regions to minimize transmissible spongiform encephalopathy risks. Such measures ensure compliance with regulatory guidelines, reducing prion infectivity by several log reductions without compromising BSA integrity.^[49]

Recombinant Production

Recombinant bovine serum albumin (rBSA) is produced by cloning the bovine ALB gene into heterologous expression systems, with the coding sequence often codon-optimized to match the host's preferences for improved translation efficiency. Common hosts include the methylotrophic yeast Pichia pastoris, the bacterium Escherichia coli, and plant-based systems such as transgenic rice seeds, enabling scalable production without relying on animal-derived materials. In P. pastoris, the gene is typically integrated into the genome under an inducible promoter like AOX1, fused to a secretion signal peptide (e.g., alpha-factor) to facilitate extracellular expression and simplify downstream processing.^[50]^[51] The production process involves fermentation in bioreactors, where optimized conditions such as methanol induction in P. pastoris can achieve yields of up to 10-20 g/L for albumin-like proteins, though specific rBSA yields vary by strain and process. For bacterial expression in E. coli, engineered variants with enhanced thermostability allow soluble production at lower temperatures to minimize inclusion body formation, followed by refolding. In rice seeds, the gene is expressed under seed-specific promoters, accumulating rBSA as up to 10% of total soluble protein for cost-effective harvesting. Purification typically employs affinity chromatography using His-tags or ion-exchange methods, alongside precipitation techniques, yielding diagnostic and molecular biology grades with >99% purity.^[52]^[53] Key advantages of rBSA include its animal-free origin, which eliminates risks of bovine spongiform encephalopathy (BSE) transmission and batch-to-batch variability associated with native extraction from bovine plasma. It offers consistent quality, including uniform post-translational modifications where applicable, and scalability through microbial or plant fermentation, reducing costs compared to traditional methods. Commercial rBSA products emerged in the late 2000s to early 2010s, with diagnostic-grade versions providing functionality equivalent to native BSA in applications like protein stabilization and blocking non-specific binding in assays. Recent advancements, such as 2023 computational designs for bacterial hosts and optimized fungal expression in filamentous species, further lower production costs and enhance thermostability for industrial scalability.^[54]^[50]

Applications

Laboratory and Research Uses

Bovine serum albumin (BSA) serves as a widely used protein standard in colorimetric assays such as the Bradford, Lowry, and bicinchoninic acid (BCA) methods due to its consistent molecular weight of approximately 66.5 kDa and reliable reactivity with assay reagents.^[55] In the Bradford assay, BSA is typically employed to generate calibration curves from stock solutions at concentrations of 0.1–1 mg/mL, enabling accurate quantification of unknown protein samples across a linear range of 0.006–1.4 mg/mL.^[56]^[57] Similarly, for the Lowry assay, BSA is preferred as a standard when analyzing serum or albumin-rich samples, providing precise measurements through its interaction with copper ions and Folin-Ciocalteu reagent.^[58] The BCA assay also utilizes BSA standards for its compatibility with reducing agents, ensuring reproducible results in biochemical analyses.^[59] As a blocking agent, BSA minimizes non-specific binding in immunological techniques including enzyme-linked immunosorbent assay (ELISA), Western blotting, and immunohistochemistry by occupying unoccupied sites on surfaces such as microtiter plates, membranes, or tissue sections.^[60] Concentrations of 0.1–5% BSA in phosphate-buffered saline or Tris-buffered saline are commonly applied during blocking steps, with 5% BSA often preferred for phosphoprotein detection to avoid interference from milk-based blockers.^[61] In Western blotting, BSA enhances signal specificity by reducing background noise, particularly when using biotin- or alkaline phosphatase-labeled antibodies.^[62] For immunohistochemistry, BSA at 2–5% stabilizes antibody interactions and improves tissue staining clarity.^[63] BSA functions as a supplement in cell culture media, such as Dulbecco's Modified Eagle Medium (DMEM), to facilitate nutrient transport, stabilize proteins, and support cell proliferation in serum-free or low-serum conditions.^[64] It is often added at 0.1–1% to mimic aspects of fetal bovine serum (FBS), providing essential fatty acid binding and protection against oxidative stress in mammalian cell lines.^[3] In cryopreservation protocols, BSA acts as a cryoprotectant additive at 2–30 mg/mL, enhancing post-thaw viability of cells like mesenchymal stem cells and spermatozoa by stabilizing membranes and reducing ice crystal damage during freezing.^[65] For instance, 2% BSA combined with dimethyl sulfoxide improves recovery rates in hematopoietic stem cell storage.^[66] BSA is employed as a model protein in binding studies owing to its well-characterized ligand-binding sites in domains IIA and IIIA, which facilitate investigations into protein-drug interactions and stability under various conditions.^[67] Its globular structure and solubility make it ideal for nanoparticle formation, where BSA nanoparticles are synthesized via desolvation or emulsification to encapsulate cargos like small molecules or nucleic acids.^[68] Recent protocols from 2023–2024 have utilized PEI-coated or anionic BSA nanoparticles for CRISPR/Cas9 delivery, achieving efficient ribonucleoprotein transfection in cell lines with reduced toxicity compared to viral vectors.^[69] These BSA-based vehicles demonstrate high loading capacity and targeted genome editing, as seen in studies targeting inflammatory pathways.^[70]

Biomedical and Industrial Applications

Bovine serum albumin (BSA) has emerged as a key component in drug delivery systems, particularly through nanoparticle formulations for targeted cancer therapy. BSA-PEG conjugates form biocompatible nanoparticles that encapsulate chemotherapeutic agents like doxorubicin (DOX), enabling pH-responsive release in tumor microenvironments. These nanoparticles achieve drug loading efficiencies of approximately 20-30%, facilitating controlled delivery and reducing systemic toxicity in breast cancer models.^[71] Recent innovations include BSA-based hydrogels developed in 2024, which incorporate thiolation and crosslinking with collagen-like proteins to enhance self-healing properties and promote wound healing. In diabetic murine and zebrafish models, these hydrogels accelerated tissue repair by improving cellular migration, reducing inflammation, and upregulating epidermal differentiation proteins compared to standalone BSA gels.^[72] In vaccine formulations, BSA serves as a stabilizer to preserve antigen integrity during storage and administration, particularly in products like certain vaccines such as MMR-II where trace amounts maintain structural stability.^[73] In food science research, BSA acts as an emulsifier in oil-in-water emulsions, enhancing stability through adsorption at oil-water interfaces and preventing droplet coalescence for potential applications in products such as dairy and beverages.^[74] For tissue engineering, BSA-derived scaffolds provide a biocompatible matrix that supports cell adhesion and proliferation. Glycosylated and PEGylated BSA forms sponge-like three-dimensional structures mimicking the extracellular matrix, promoting attachment of fibroblasts like NIH 3T3 cells through enhanced surface interactions. Additionally, recombinant BSA is integrated into serum-free media for cultivated meat production, replacing animal-derived components to enable scalable differentiation of bovine satellite cells, as demonstrated in studies from 2023-2025 that achieved viable cell growth without fetal bovine serum.^[75]^[76] Emerging applications include biosensors leveraging recombinant BSA domains for detecting contaminants like ochratoxin A (OTA). In 2025 research, the domain II of recombinant BSA (rBDII), produced in E. coli, was immobilized on solid-phase extraction columns, achieving up to 84% recovery of OTA from spiked grape juice with binding constants of 5.7–9.3 × 10⁴ M⁻¹, enabling sensitive food safety monitoring. The global BSA market is projected to grow at a compound annual growth rate (CAGR) of 3% through 2031, driven by increasing demand in biotechnology for therapeutics and diagnostics.^[77]^[78]

References

[1]
None
### Key Facts About BSA
[2]
Bovine Serum Albumin Interactions with Metal Complexes - PMC - NIH
Nov 12, 2014 · The aim of this review is to focus on the structure and biological functions of bovine serum albumin, the design of metal complexes that are able to bind to ...
[3]
Albumin and mammalian cell culture: implications for biotechnology ...
Structure and biochemical properties influencing albumin function. To enable a clearer appreciation of the basis for a biological function in cells and an ...
[4]
Serum Albumin - an overview | ScienceDirect Topics
Bovine Serum Albumin (BSA) is defined as the most abundant protein in cow's blood serum, constituting approximately 50% of its protein content, ...
[5]
ALB - Albumin - Bos taurus (Bovine) | UniProtKB | UniProt
Albumin (P02769) regulates blood osmotic pressure, binds water, Ca2+, Na+, K+, fatty acids, hormones, bilirubin, drugs, and is a major zinc transporter.
[6]
Physiology, Albumin - StatPearls - NCBI Bookshelf - NIH
Albumin is the most abundant circulating protein found in plasma. It ... In the laboratory, bovine serum albumin is used as a laboratory standard.[5][6] ...
[7]
[PDF] Bovine Serum and Bovine Serum Albumin (BSA) for Laboratory ...
Apr 16, 2019 · The slaughtered bovine animals from which the blood and/or blood product was derived: a. Passed ante-mortem inspection; and b. Were not ...Missing: taurus waste
[8]
https://www.govinfo.gov/content/pkg/FR-2007-01-09/pdf/07-17.pdf
[9]
[PDF] Federal Register/Vol. 72, No. 5/Tuesday, January 9, 2007/Proposed ...
Jan 9, 2007 · In current §§ 93.400, 94.0, and 95.1 of the regulations, bovine is defined as Bos taurus, Bos indicus, and ... bovine serum was derived was ...
[10]
Original domain for the serum albumin family arose from repeated ...
The characteristic three-domain structure has been conserved throughout mammalian evolution by serum albumin and its fetal counterpart, alpha-fetoprotein.
[11]
Original domain for the serum albumin family arose - PNAS
ABSTRACT The characteristic three-domain structure has been conserved throughout mammalian evolution by serum al- bumin and its fetal counterpart, ...
[12]
The History Behind Bovine Serum Albumin - Lifecycle Biotechnologies
Oct 5, 2017 · Dr. Edwin Cohn developed what became known as the Cohn process, a number of purification steps to extract albumin from blood plasma. Dr. Cohn ...
[13]
Edwin Cohn developed cold ethanol fractionation - Life Science
In 1940, Edwin Cohn, a professor of biological chemistry at Harvard Medical School, developed cold ethanol fractionation, the process of breaking down plasma ...
[14]
The past, present and future of blood plasma fractionation
Cohn's group started to develop new methods of fractionation using ethanol-water mixtures in 1940. Wartime concerns for the provision of plasma substitutes for ...
[15]
The development of albumin solutions in the Second World War - NIH
Jul 6, 2023 · Clinical testing of bovine albumin began in April 1941, and proceeded for almost 2 years. Intravenous injections were initially administered to ...
[16]
Part I. Bovine Albumin - AMEDD Center of History & Heritage
The bovine albumin program in World War II began in late 1940and progressed in a series of highly encouraging developments until July 1942.
[17]
Bovine Derived Materials Used in Vaccine Manufacturing Questions ...
Mar 23, 2018 · However, FDA wants to minimize any chance that the BSE agent could be introduced into biologic products during manufacture. The Center for ...Missing: impact | Show results with:impact
[18]
https://dyadic.com/dyadic-announces-continued-progress-towards-commercialization-of-animal-free-recombinant-serum-albumin/
[19]
Dyadic Announces Continued Progress Towards Commercialization ...
Aug 7, 2023 · Dyadic has developed animal-free recombinant bovine and human serum albumin, with testing showing it is structurally equivalent to commercial ...Missing: studies | Show results with:studies
[20]
TALEN-Mediated Modification of the Bovine Genome for Large ...
Feb 21, 2014 · We report modification of the bovine albumin (bA) locus by transcription activator-like effector nuclease (TALEN)-stimulated homology-directed repair (HDR).
[21]
Bovine Serum Albumin - an overview | ScienceDirect Topics
Bovine serum albumin (BSA) is the most abundant protein in the circulatory system and constitutes approximately 50% of the protein in the cow's blood serum.Missing: BSE production post-
[22]
Structural and Biochemical Features of Human Serum Albumin ... - NIH
Aug 5, 2021 · A crucial factor in FBS is bovine serum albumin (BSA), which accounts for >95% of the protein content of the serum, along with small amounts of ...
[23]
Formation and reshuffling of disulfide bonds in bovine serum ...
Jul 20, 2015 · The primary structure of BSA was first reported in 1971 and later revised in 1990. BSA contains 583 amino acids of which one Cys and seventeen ( ...
[24]
Albumin: A Review of Market Trends, Purification Methods, and ...
The isoelectric point (pI) of OVA is 4.8, with a molecular weight of 47,000 Da [15]. In comparison, BSA has a molecular weight of 69,324 Da and a pI of 4.7; ...<|control11|><|separator|>
[25]
Conformational change of bovine serum albumin by heat treatment
The thermal denaturation of bovine serum albumin (BSA) was studied at pH 2.8 and 7.0 in the range of 2-65 degrees C.
[26]
Kinetics of Thermal Denaturation and Aggregation of Bovine Serum ...
Apr 21, 2016 · Thermal denaturation of the protein was studied by differential scanning calorimetry. Analysis of the experimental data shows that at 65°C the ...
[27]
https://pubmed.ncbi.nlm.nih.gov/23838624/
[28]
Fatty acid binding sites of human and bovine albumins
Serum albumin is a major transport protein in mammals and is known to have at least seven binding sites for long-chain fatty acids (FAs).
[29]
Multi-spectroscopic investigation of the binding interaction of ...
Sudlow et al. [28] suggested two main distinct binding sites (sites I and II) in BSA. Site I of BSA has affinity for warfarin and site II for ibuprofen. It ...
[30]
and low-affinity bilirubin-binding sites on serum albumin ... - PubMed
Jun 22, 2013 · The locations of three bilirubin (BR)-binding sites with different affinities were identified as subdomains IB, IIA and IIIA for five ...
[31]
Human Serum Albumin Loaded with Fatty Acids Reveals Complex ...
Lyophilized powder of HSA (>95%, Calbiochem), 16-DSA (Sigma-Aldrich) and 87 wt % glycerol (ACROS Organics) were used without further purification. The 0.137 M ...
[32]
Binding, Self-Assembly and Interaction with Bovine Serum Albumin
Jun 12, 2019 · Fluorescence spectroscopy is a valuable tool for studying ligand-protein interactions. BSA contains two tryptophan residues, Trp134 and Trp213 ...
[33]
a comparative study of the two and one tryptophan(s) of bovine and ...
Differences in the fluorescence behavior of the proteins are attributed to the fact that Trp-134 exists only in BSA, with the assumption that Trp-213 of BSA ...Missing: quenching | Show results with:quenching
[34]
Oncotic Pressure - an overview | ScienceDirect Topics
Normally, the plasma oncotic pressure averages 28 mm Hg.3,4. Albumin is the primary plasma protein that is responsible for approximately 80% of the total COP.
[35]
The role of albumin in critical illness - Oxford Academic
35 In health, albumin contributes up to 80% of the normal COP of about 25 mmHg.34 101 106 This is because of its high molecular weight and concentration in ...
[36]
Serum Albumin in Health and Disease: Esterase, Antioxidant ...
This review considers the esterase, antioxidant, transporting and signaling properties of albumin, as well as its structural and functional modifications
[37]
Effects of free fatty acids on the binding of steroid hormones to ...
The effects of binding of free fatty acids (FFA) to bovine serum albumin (BSA) on steroid hormone binding to BSA were examined.Missing: transport thyroxine
[38]
Competitive Binding of Bilirubin and Fatty Acid on Serum Albumin ...
May 10, 2020 · Bilirubin binds to hydrophobic binding sites in BSA. The binding of bilirubin causes conformational changes in the BSA molecule [27]. These ...<|separator|>
[39]
[PDF] Isolation of bovine plasma albumin by liquid chromatography and its ...
Characteristics of 22% (w/v) bovine albumin (N = 12). Albumin in the plasma pool. 35.0 g/l. Yield. 25.0 ± 1.2 g/l plasma. Recovery. 71.5 ± 1.5%. Protein. 22.0 ± ...
[40]
Albumin - eClinpath
Albumin makes a large contribution to plasma colloid osmotic pressure due to its small size and abundance (35-50% of total plasma proteins by weight). It ...
[41]
FcRn mediates elongated serum half-life of human IgG in cattle
Interestingly, FcRn also binds albumin and prolongs its half-life in a concentration-dependent manner like is seen for IgG (21, 22). In cattle, the serum ...
[42]
Antioxidant effect of bovine serum albumin on membrane lipid ...
Albumin is supposed to be the major antioxidant circulating in blood. This study examined the prevention of membrane lipid peroxidation by bovine serum ...Missing: activity | Show results with:activity
[43]
The antioxidant properties of serum albumin - Roche - FEBS Press
May 12, 2008 · In plasma, most of the copper is bound to caeruloplasmin, but a high percentage of the metal ion may exist bounded to albumin [13]. HSA ...
[44]
Anticoagulant action of low, physiologic, and high albumin levels in ...
Aug 11, 2017 · Anticoagulant action of low, physiologic, and high albumin levels in whole blood. Margret Paar. Margret Paar. 1Institute of Physiological ...
[45]
Human Serum Albumin Binds Streptolysin O (SLO) Toxin Produced ...
Dec 8, 2020 · HSA binds SLO with high affinity at a non-conventional site located in domain II, which was previously reported to interact also with C. difficile toxins.
[46]
Clinical Significance of Serum Albumin and Implications of FcRn ...
We describe the anti-inflammatory and antioxidant properties of SA, as well as its ability to bind and transport a plethora of endogenous and exogenous ...
[47]
Composition and properties of bovine colostrum: a review
Sep 14, 2015 · The concentration of bovine serum albumin in colostrum is higher than in milk (Zhang et al. 2011). Perez et al. (1989) reported that the first ...
[48]
[PDF] The Cohn Process - LearnChemE
This process was successful for separating albumin from blood plasma. It involved chilled ethanol that initially recovered ~85% of the albumin in whole blood, ...
[49]
(PDF) Ammonium sulfate precipitation combined with liquid ...
Aug 6, 2025 · Ammonium sulfate precipitation combined with liquid chromatography is sufficient for purification of bovine serum albumin that is suitable for most routine ...
[50]
Overview of Albumin and Its Purification Methods - PMC - NIH
Knowing this, Serum albumin is a nobility biomarker for liver function synthesis, and also for several diseases, such as, inflammatory disorders, brain tumors, ...
[51]
[PDF] Ammonium sulfate precipitation combined with liquid ...
Aug 1, 2013 · Conventional purification of BSA is based on the original Cohn method [6,7] which involved pH and ethanol precipitations. Recent modifications ...Missing: shock | Show results with:shock
[52]
[PDF] minimising-risk-transmitting-animal-spongiform-encephalopathy ...
Mar 5, 2011 · For the classification of countries or regions according to their BSE risk, the revised Note for Guidance will make reference to the rules ...Missing: impact | Show results with:impact
[53]
Eliminating Spiked Bovine Spongiform Encephalopathy Agent ... - NIH
We found NaOH treatment and DE filtration to be the most effective steps for removing both BSE infectivity and PrPTSE seeding activity, consistent with previous ...
[54]
Stability of BSE infectivity towards heat treatment even after ...
Apr 16, 2021 · Such test could have yielded information whether in case of BSE a proteolytic digestion of non-heated prion material had lead to infectivity ...
[55]
WO2006066595A2 - Recombinant production of serum albumin
The present invention relates to methods for recombinant expression of serum albu- min in a filamentous fungal host organism, to modified nucleic acid sequences ...
[56]
iScience - Serum-free cultured meat production by using Pichia ...
Jul 29, 2025 · This study uses Pichia pastoris-derived recombinant albumin to support serum-free cultured meat production, promoting cell proliferation and ...
[57]
Medium optimization for high yield production of human serum ...
High recombinant human serum albumin (rHSA) yields were recently reported (17.5 g/l) in P. pastoris by means of medium optimization [15]. Due to its efficient ...
[58]
Large-scale production of functional human serum albumin ... - PNAS
Oct 31, 2011 · We report the production of Oryza sativa recombinant HSA (OsrHSA) from transgenic rice seeds. The level of OsrHSA reached 10.58% of the total soluble protein ...
[59]
rBSA (Recombinant Bovine Serum Albumin) – Diagnostic Grade
rBSA is a non-animal derived albumin, produced in yeast, used for protein stabilization and reducing non-specific binding in assays.
[60]
Evaluation of Colorimetric Assays for Analyzing Reductively ... - NIH
Typically, BSA is used as a standard for the Bradford assay, and a calibration curve based on the mass concentration of BSA is used to determine the unknown ...
[61]
detectable limits, linear dynamic ranges, interferences, practicality ...
Bradford method was the most sensitive assay (LOD=0.006 mg/ml) and had the widest range of detectability (LOD-UOD=0.006-100mg/ml) for purified protein and ...
[62]
[PDF] Lowry Protein Assay - UF Animal Sciences
For serum, use bovine serum albumin as a standard since albumin is a major component of serum. An easy and accurate alternative, based on the binding of protein ...
[63]
Comparison of Colorimetric Assays with Quantitative Amino Acid ...
We compared protein quantification by Bradford, Lowry, and Non-Interfering assays using bovine serum albumin (BSA) as standard with quantitative amino acid (AA ...
[64]
Enzyme Linked Immunosorbent Assay - StatPearls - NCBI Bookshelf
Blocking (typically with the addition of bovine serum albumin [BSA]) ... Diagnosis requires further testing by Western blot due to potential false positives.Missing: immunohistochemistry | Show results with:immunohistochemistry
[65]
Antibody validation for Western blot: By the user, for the user - NIH
Cofilin (∼19 kDa) was detected on blots blocked with 5% BSA, 5% nonfat dry milk, or Odyssey blocking buffer. Blots were visualized with IRDye 800CW secondary ...
[66]
Western Blotting (Immunoblotting): History, Theory, Uses, Protocol ...
BSA may be preferred over milk as the blocking agent for phosphoprotein antibodies, biotin, and alkaline phosphatase (AP) labeled antibodies. The major protein ...
[67]
Bovine Serum Albumin (BSA), Standard Grade: A Critical Tool in ...
Oct 29, 2024 · In ELISA, Western blotting, and immunohistochemistry, BSA acts as a blocking agent to minimize nonspecific binding, improving assay ...
[68]
Unlocking Potential: Low Bovine Serum Albumin Enhances ... - NIH
Mar 28, 2024 · Bovine serum albumin (BSA) plays a crucial role in cell culture media, influencing cellular processes such as proliferation and differentiation.
[69]
Effects of storage media, supplements and cryopreservation ... - NIH
The manuscript is an overview of current cryopreservation protocols used for cold storage of hematopoietic stem cells, mesenchymal stem cells and induced ...
[70]
Effects of five cryoprotectants on proliferation and differentiation ...
The 30 mg/ml BSA is the most viable media for the cryopreservation of testicular tissue from cattle. Keywords: bovine calf testicular tissue; cryopreservation; ...
[71]
Recent advances in albumin-based nanoparticle drug delivery ...
Sep 4, 2025 · Clinical studies have shown decreased levels of anti-inflammatory cytokines ... Modulating the expression of pro-inflammatory cytokines and immune ...
[72]
Albumin and functionalized albumin nanoparticles: production ... - NIH
Dec 31, 2020 · The precursor protein of BSA contains 607 amino acids along its full length. Upon secretion, an 18-residue signal protein is cleaved from the N- ...
[73]
Albumin Nanoparticle-Based Drug Delivery Systems - PMC - NIH
Jul 10, 2024 · Albumin is typically negatively charged at a pH of 7 (PI=4.7), which makes it carry different types of chemotherapy drugs. Although albumin ...Missing: absorbance A280
[74]
PAR2 deficiency tunes inflammatory microenvironment to magnify ...
This work constructed anionic bovine serum albumin (BSA) nanoparticles to encapsulate CRISPR/Cas9 plasmid encoding PAR2 sgRNA and Cas9 (tBSA/Cas9-PAR2) for ...
[75]
Engineered bovine serum albumin-based nanoparticles with pH ...
Aug 5, 2020 · The engineered BSA NPs were able to efficiently load DOX with high drug loading content and encapsulation efficacy ( Table 1 ). The particle ...
[76]
Thiolation-Based Protein-Protein Hydrogels for Improved Wound ...
In comparison to standalone BSA hydrogels, these protein-protein hydrogels demonstrate enhanced cellular viability, and improved cellular migration. In vivo ...
[77]
[PDF] Vaccine Excipients by Excipient
Apr 7, 2025 · Albumin, Bovine. Stabilizer. Vaqta. HepA. <10-4 mcg. Albumin, Bovine. Stabilizer. Zostavax. Varicella Zoster. Trace amounts. Albumin, Bovine ...
[78]
Bovine Serum Albumin-Sugar Conjugates through the Maillard ...
Proteins are widely used as emulsifiers in food, cosmetic, and pharmaceutical industries to homogenize insoluble liq- uids and maintain the homogeneous ...
[79]
Scaffold materials from glycosylated and PEGylated bovine serum ...
Different surfaces for cell adhesion were achieved by crosslinking the initial albumin product and forming either a coating or a sponge-like three-dimensional ...
[80]
Supplemented serum-free media for cultured meat production
The method includes adding a recombinant version of albumin to a baseline serum-free and animal-component-free culture media. The adding produces the serum-free ...Missing: BSA | Show results with:BSA
[81]
Recombinant bovine serum albumin domain II as bioreceptor for ...
Feb 1, 2025 · This study aimed at exploring the BSA domain II (BDII), which houses the primary binding site for ochratoxin A (OTA), as a bioreceptor for OTA capture.
[82]
Bovine Serum Albumin Market Trends and Forecast (2021-2031)
The Bovine Serum Albumin Market is expected to register a CAGR of 3% from 2025 to 2031, with a market size expanding from US$ XX million in 2024 to US$ XX ...