Bovine Serum Albumin (BSA) — All Grades | EU/US/NZ Origin
Bovine Serum Albumin (BSA) is one of the most widely used proteins in life science research. As a cell culture supplement, blocking reagent, enzyme stabiliser, and protein quantification standard, BSA is present in virtually every biochemistry and cell biology laboratory. SeamlessBio supplies BSA Fraction V in five quality grades, sourced from certified herds in the EU, USA, Australia, and New Zealand.
Selecting the correct BSA grade is critical — the wrong grade introduces unwanted fatty acids, excessive endotoxin, or interfering proteases into sensitive assays. The table below guides selection by application.
BSA Grade Comparison
| BSA Grade | Key Properties | Primary Applications | Order |
|---|---|---|---|
| Standard Grade | ≥96% purity, Fraction V | General cell culture, protein assays, general blocking | Shop → |
| Low Endotoxin | ≤5 EU/mg, ≥98% | Primary cell culture, stem cells, sensitive assays | Shop → |
| Fatty Acid-Free | FA-free, ≥98% | Lipid/fatty acid research, membrane assays, drug binding | Shop → |
| pH 5.2 | ≥96%, adjusted to pH 5.2 | Acidic assay systems, pH-dependent binding studies | Shop → |
What is BSA Fraction V?
BSA Fraction V refers to the fifth fraction obtained during Cohn ethanol fractionation of bovine serum — the fraction enriched in albumin. With a molecular weight of approximately 66.5 kDa and an isoelectric point of ~4.7, BSA Fraction V is the standard starting material for all downstream BSA purification grades. Fraction V is soluble, monomeric, and highly stable under standard laboratory conditions.
Core Applications of BSA
| Application | BSA Role | Recommended Grade |
|---|---|---|
| Cell culture media supplement | Carrier for lipids, hormones, trace elements; osmotic balance | Low Endotoxin or High-purity Grade |
| ELISA / IHC blocking | Saturates non-specific binding sites on plates and membranes | Standard or Low Endotoxin |
| Western blot blocking | Blocks membrane before antibody incubation (alternative to milk) | Standard — preferred for phospho-protein blots |
| Enzyme stabilisation | Protects enzymes in restriction digests, PCR reactions | Standard (protease-free) |
| Protein quantification standard | BSA serial dilution as reference curve (BCA, Bradford, Lowry) | Standard |
| Albumax substitute (P. falciparum culture) | Lipid carrier for intraerythrocytic parasite culture | Fatty Acid-Free (supplemented with lipids) |
| Drug binding / displacement assays | Fatty acid-free BSA as defined binding substrate | Fatty Acid-Free |
| Stem cell and primary cell culture | Xeno-reduced supplement, albumin source | High-purity Grade Low Endotoxin |
| GMP-adjacent bioprocessing | Defined protein supplement in process media | High-purity Grade Low Endotoxin |
Purification Methods — Heat Shock vs Cohn
Most standard BSA grades on the market are purified by the classical Cohn ethanol fractionation method. SeamlessBio's
Origin and Traceability
| Origin | Notes | When to specify |
|---|---|---|
| EU / Europe | EU cattle herds, EU-compliant collection | Default for EU regulatory submissions |
| USA | USDA-certified herds, BSE-free | FDA IND/BLA packages requiring US-origin documentation |
| Australia / New Zealand | OIE BSE-free, CEP/EDQM available for Ph. Eur. compliance | Strictest BSE safety requirement; Ph. Eur. ancillary material |
General Specifications
| Parameter | Standard range |
|---|---|
| Molecular weight | ~66,500 Da (66.5 kDa) |
| Purity | ≥96–98% depending on grade |
| Form | Lyophilised powder or solution (grade dependent) |
| Storage | +4 °C (solution) or −20 °C (lyophilised, long-term) |
| Pack sizes | 5 g, 10 g, 50 g, 100 g, 500 g, 1 kg | Bulk on request |
| Documentation | CoA, CoO, MSDS on request |
| Minimum order | None |
Questions or bulk pricing: info@seamlessbio.de | +49 851 37932226