计算溶液所需的质量、体积或浓度。
BioReagent,通过内毒素测试 级 ,适用于对基线干扰要求严格的色谱和分析工作流程。
2-8°C储存,禁止冷冻。低温运输,禁止冷冻 。请查阅批次 COA 获取详细规格。
SDS、COA、产品数据表及规格说明书均可下载。可通过批号查询获取批次 COA。
在色谱分析、有机合成和交叉偶联反应领域已被 0 篇同行评审文献引用。
储存缓冲液:20% (v/v) Ethanol
本产品是链霉亲和素的突变体(ST2配基)和琼脂糖凝胶偶联形成的层析分离介质,用于分离、纯化Strep II或Twin Strep标签蛋白。Strep II标签为8个氨基酸的小标签(WSHPQFEK),一般不影响融合后蛋白质的结构和功能,常用于融合表达蛋白质的检测和纯化。Twin Strep 标签为两个 Strep II串联的标签,相比Strep II标签,Twin Strep标签与ST2配基的亲和力更高。
本产品的ST2配基与上一代ST配基相比,对Strep II标签的亲和力进一步提高,与生物素的亲和力大幅削弱。因而本产品能够更牢固的结合Strep II融合蛋白,在融合蛋白表达丰度较低时,相对捕获量更高,载量和得率更高。在洗脱方面,可以使用生物素进行洗脱,比采用昂贵的脱硫生物素洗脱更经济,且使用后可采用10~50 mM NaOH 进行再生。本产品对Strep II标签具有高度特异性,一般只需一步纯化就能获得高纯度的蛋白质样品。
阿拉丁Strep II 亲和层析介质(耐生物素)储存在20%乙醇中,凝胶和保护液的体积比为1:1,我司产品规格为实际凝胶的体积。
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注:
① 90%体积以上的微球在此粒径范围;
② 测试结果为单位体积填料纯化菌体获得的纯蛋白量(带Strap II 标签的增强型绿色荧光蛋白),该结果与DBC10%结果相当;
③ 10cm柱高下的最大测试流速。

图1. Strep II 亲和层析介质(耐生物素)与带 Strep II、Twin Strep 标签蛋白之间的特异性结合
图2. Strep II 亲和层析介质(耐生物素)纯化带Strep II标签蛋白的过程
使用说明
1、色谱柱装填
以下阐述与层析系统连接时,填料的色谱柱装填方法。
(1)所有需要用到的材料的温度要与色谱操作的温度一样,液体最好做脱气处理。
(2)填料用量计算:通过沉降定量填料体积,需要的沉降填料体积=柱体积×压缩比(也称压缩因子)。沉降体积是指填料在20%乙醇保存液中自然沉降完全读取的稳定体积。Strep II 亲和层析介质(耐生物素)的压缩比为1.15。为使达到装柱比,可通过柱头下压的方法,也可以通过高流速压柱。
(3)填料清洗:将填料悬液充分摇匀后量取相应体积,抽滤除去液体,并用约3倍填料体积的纯化水洗涤,重复3次,以除去保存液。
(4)装柱填料悬液准备:将填料转移到适当的容器中,加入适量的装柱液,制成 50~75 v%的装柱填料悬液,使用前搅匀。
(5)装填前准备:在清洗干净的层析柱下端加入装柱液,以除去下垫片及层析柱下端的空气,在柱内保留少量的蒸馏水,拧紧下堵头,调整柱子使其垂直于地面。
(6)装填:将搅匀后的填料悬液一次性缓慢倒入层析柱内(必要时使用装柱器),为避免引入气泡,应使之沿层析柱内壁自然流下。将所有填料加入后,用装柱液将装柱器加满,拧紧装柱器上盖,将柱子与层析系统连接。
(7)压柱:使柱内填料自然沉降(或50~150 cm/h的低流速下沉降),待填料沉降完全后(填料与液体的界面清晰),去除装柱器,装上上柱头,并将柱头下降至界面处; 通过高流速(推荐流速见下表,注意柱压不超过0.3 MPa),继续压柱至界面清晰稳定,标记界面稳定时的柱高。停泵,打开柱头上的阀门/堵头,关闭柱底的阀门/堵头,下压柱头至标记位置下方与压缩比对应的位置,旋紧柱头,装柱完成。装柱完成后,需用高流速平衡柱内的填料。
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2、柱效测定和评价
完成装柱后、使用前可通过柱效测定和评价可以确认层析柱装填质量。柱效通常用理论塔板高度(HETP)和非对称因子(As)来评价。
柱效测定可以采用丙酮或者NaCl作为样品进行,按照下表配制样品溶液和流动相。
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根据UV或者电导率曲线计算理论塔板高度(HETP)、理论塔板数(N)和非对称因子(As),公式如下:
HETP = L / N
N = 5.54 × (Vʀ / Wₕ)²
As = a / b
其中:L为柱高; Vʀ为保留体积;Wₕ为半高峰宽;a为在10%峰高处的第一个半峰宽;b为在10%峰高处的第二个半峰宽。
一般来说,HETP的数值应小于填料平均粒径的三倍(即HETP/D50<3,D50为填料的平均粒径),As应在0.8~1.5之间。
3、平衡与上样
StrepⅡ 亲和层析介质(耐生物素)的工作pH范围为6~10,推荐下述缓冲液A为平衡与上样缓冲液。样品需作澄清处理,并用缓冲液A稀释或者换液成缓冲液A。
缓冲液A:100mM Tris-HCl,150mM NaCl,1mM EDTA,pH8.0。
平衡5个柱体积,建议流速为~150 cm/h;上样流速为50~150cm/h,较小的流速有利于载量的提高,可根据实际结合情况选择流速,能获得较好的效果。
4、再平衡
上样后用缓冲液 A 再平衡5~10 CV,或平衡至基线,洗去杂质,推荐流速为~150 cm/h。
5、洗脱
推荐含10~50 mM的D-生物素作为洗脱缓冲液,如下述的缓冲液B。
缓冲液B:50mM d-Biotin,100 mM Tris-HCl,150 mM NaCl,1 mM EDTA,pH8.0。
用洗脱缓冲液洗6-10 CV,建议流速为~150 cm/h。
6、再生
在一次或多次使用后,需要对填料进行再生:水,3~5 CV,~150 cm/h;10~50 mM NaOH,3 CV,3 min 接触时间;水,3~5 CV,~150 cm/h;再用缓冲液A平衡5~10 CV, ~150 cm/h。
7、填料保存
填料的初始保存液为20%乙醇,使用过后可继续用20%乙醇保存。保存温度在2~8 ℃ 为宜,不可冻存。
This product is a chromatography separation medium formed by coupling a streptavidin mutant (ST2 ligand) to agarose gel. It is designed for the separation and purification of Strep-tag II or Twin-Strep-tag proteins. The Strep-tag II is a small 8-amino acid tag (WSHPQFEK) that generally does not affect the structure or function of the fused protein, making it widely used for the detection and purification of fusion proteins. The Twin-Strep-tag consists of two tandem Strep-tag II sequences and exhibits higher affinity for the ST2 ligand compared to the single Strep-tag II.
The ST2 ligand in this product shows further enhanced affinity for Strep-tag II and significantly reduced affinity for biotin compared to the previous ST ligand. This allows for stronger binding to Strep-tag fusion proteins, higher relative capture efficiency at low expression levels, and increased binding capacity and yield. For elution, biotin can be used instead of the more expensive desthiobiotin, making the process more economical. After use, the medium can be regenerated with 10–50 mM NaOH. The product offers high specificity for the Strep-tag, typically enabling high-purity protein samples in a single purification step.
Aladdin Strep II Agarose Resin (Biotin-Resistant) is stored in 20% ethanol, with a settled gel to storage solution ratio of 1:1. The product specification refers to the actual volume of the settled gel.
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Notes:
① Over 90% of the beads fall within this size range.
② Binding capacity measured as pure protein yield (enhanced green fluorescent protein with Strep-tag II) per mL resin; comparable to DBC₁₀%.
③ Maximum tested flow rate at 10 cm column height.
Protocol
1. Column Packing
The following procedure describes column packing when connected to a chromatography system:
(1) Equilibrate all materials to the operating temperature. Degas liquids if possible.
(2) Resin Quantity Calculation:
Settled resin volume = Column volume × Compression factor (1.15 for this resin).
(3) Resin Preparation: Resuspend the resin slurry thoroughly. Measure the required volume, remove storage solution by filtration, and wash 3 times with ~3 resin volumes of purified water.
(4) Packing Slurry Preparation: Transfer resin to a suitable container and add packing solution to achieve a 50–75% (v/v) slurry. Mix well before use.
(5) Pre-packing Setup: Fill the bottom of the clean column with packing solution to remove air from the bottom frit and outlet. Retain a small amount of liquid, tighten the bottom end fitting, and ensure the column is vertical.
(6) Packing: Pour the well-mixed slurry into the column in one slow, continuous motion (use a packing reservoir if needed). After adding all resin, fill the reservoir with packing solution, attach the top lid, and connect the column to the system.
(7) Compression: Allow the resin to settle naturally (or use a low flow rate of 50–150 cm/h). Apply a high flow rate (600 cm/h; ensure pressure ≤0.3 MPa) until the interface is stable. Mark the stable height, stop the pump, and lower the adapter to the position corresponding to the compression factor (1.15). Tighten the adapter and equilibrate the column at a high flow rate.
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2. Column Efficiency Testing
After packing, assess column efficiency using HETP (Height Equivalent to a Theoretical Plate) and As (Asymmetry Factor) with acetone or NaCl as tracers:
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Calculate HETP, N, and As using:
HETP = L / N
N = 5.54 × (Vʀ / Wₕ)²
As = a / b
HETP should be <3× the average particle diameter (HETP/D₅₀ < 3), and As should be 0.8–1.5.
3. Equilibration and Loading
Recommended Buffer A (Binding/Equilibration Buffer): 100 mM Tris-HCl, 150 mM NaCl, 1 mM EDTA, pH 8.0.
Clarify the sample and dilute/exchange it into Buffer A.
Equilibrate with 5 CV of Buffer A at ~150 cm/h.
Load sample at 50–150 cm/h; lower flow rates may improve binding capacity.
4. Washing
Wash with 5–10 CV of Buffer A at ~150 cm/h until baseline stabilizes.
5. Elution
Recommended Buffer B (Elution Buffer): 50 mM D-biotin, 100 mM Tris-HCl, 150 mM NaCl, 1 mM EDTA, pH 8.0.
Elute with 6–10 CV of Buffer B at ~150 cm/h.
6. Regeneration
After one or multiple uses, regenerate the resin as follows:
Water: 3–5 CV, ~150 cm/h
10–50 mM NaOH: 3 CV, 3 min contact time
Water: 3–5 CV, ~150 cm/h
Re-equilibrate with 5–10 CV of Buffer A at ~150 cm/h
7. Storage
Store in 20% ethanol at 2–8°C. Do not freeze.