英文名稱：Albumin from bovine serum，BSA，Cohn Fraction V

CAS號：9048-46-8
分子量： 約66 kD
級別：Biotech Grade
溶解度：水中溶解度為40 mg/ml, 溶液淺黃色至黃綠色。
Purity: ≥98.0%
性狀：白色至淡黃色粉末
安全防護：可能會造成皮膚過敏，引起呼吸道刺激。

牛血清白蛋白，英文名稱為Bovine Serum Albumin，也稱Bovine albumin，或Cohn Fraction V，簡稱BSA。BSA有著極其廣泛的實驗室應用，在免疫實驗中常用作封閉劑，包括ELISA、WB（Western Blot）。作為載體蛋白，將其交聯于半抗原和其他弱抗原可以使它們在抗體生產中具有更強的免疫原性。在限制性內切酶消化反應中，BSA常常被用作一些酶的反應穩定劑，并且能防止它粘附到管壁和槍頭上。BSA也常用于生物制藥的生產過程或者作為營養物用于細胞和微生物培養。除此之外，還作為蛋白定量檢測的標準品使用。

本級別的牛血清白蛋白（BSA, Standard Grade），可以滿足大部分常規實驗需求，如用作免疫封閉劑、組織細胞培養添加劑、蛋白/酶穩定劑以及蛋白定量標準品。

注意事項 

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運輸與存儲 常溫運輸，2-8℃冷藏保存。有效期 3年

本試劑僅適用于實驗室科研用途！

Bovine serum albumin (also known as BSA or "Fraction V") is a serum albumin protein derived from cows. It is often used as a protein concentration standard in lab experiments.

The nickname "Fraction V" refers to albumin being the fifth fraction of the original Edwin Cohn purification methodology that made use of differential solubility characteristics of plasma proteins.

Applications

BSA has numerous biochemical applications including ELISAs (Enzyme-Linked Immunosorbent Assay), immunoblots, and immunohistochemistry. Because BSA is a small, stable, moderately non-reactive protein, it is often used as a blocker in immunohistochemistry. During immunohistochemistry, which is the process that uses antibodies to identify antigens in cells, tissue sections are often incubated with BSA blockers to bind nonspecific binding sites. This binding of BSA to nonspecific binding sites increases the chance that the antibodies will bind only to the antigens of interest. The BSA blocker improves sensitivity by decreasing background noise as the sites are covered with the moderately non-reactive protein.  During this process, minimization of nonspecific binding of antibodies is essential in order to acquire the highest signal to noise ratio. BSA is also used as a nutrient in cell and microbial culture. In restriction digests, BSA is used to stabilize some enzymes during the digestion of DNA and to prevent adhesion of the enzyme to reaction tubes, pipette tips, and other vessels. This protein does not affect other enzymes that do not need it for stabilization. BSA is also commonly used to determine the quantity of other proteins, by comparing an unknown quantity of protein to known amounts of BSA (see Bradford protein assay). BSA is used because of its ability to increase signal in assays, its lack of effect in many biochemical reactions, and its low cost, since large quantities of it can be readily purified from bovine blood, a byproduct of the cattle industry. Another use for BSA is that it can be used to temporarily isolate substances that are blocking the activity of the enzyme that is needed, thus impeding polymerase chain reaction (PCR).