MAL-dPEG ® NHS ester-1000 mg

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MAL-dPEG®24-NHS ester, product number QBD-10314, is a crosslinking reagent that joins a sulfhydryl to a free amine through a hydrophilic bridge. The sulfhydryl groups react with a maleimide group via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the N-hydroxysuccinimidyl (NHS) ester of a carboxylic acid group. The maleimide and NHS functional groups on the crosslinking compound sit at either end of a long, discrete-length polyethylene glycol chain (dPEG®). Reactions that join free amines with free thiols are among the most popular, most useful crosslinking reactions in bioconjugate chemistry. These reactions require heterobifunctional reagents that bridge the two groups. Traditional crosslinkers are hydrophobic molecules. Vector Laboratories' dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths. The conjugation of conventional hydrophobic crosslinking reagents to biomolecules almost inevitably triggers problems such as aggregation and precipitation of the conjugates. These problems do not occur with our water-soluble, non-immunogenic dPEG® crosslinkers. Because NHS esters hydrolyze readily in water or aqueous buffer, the NHS ester end of the molecule must conjugate to a target molecule before conjugating the maleimide end of the molecule. At pH 7.0 – 7.5, NHS esters react optimally with free amines. However, NHS esters can react with free amines with pH as low as 6.5. As the pH increases, the hydrolysis rate of the NHS ester increases. Indeed, at pH 8 and 25°C, the half-life of an NHS ester in aqueous media is one hour, while at pH 8.6 and 4°C, the half-life falls to ten (10) minutes.[3] Thus, we strongly discourage storing MAL-dPEG®24-NHS ester, product number QBD-10314, in water or aqueous buffer. Instead, we recommend that customers make new solutions of the product as needed, use them immediately, and discard unused solutions after use. The reaction of the maleimide end of MAL-dPEG®24-NHS ester with a sulfhydryl proceeds optimally at pH 6.5 – 7.5. Use the lowest reasonable pH within this range. Above pH 7.5, free amines compete with free thiols at the maleimide reaction site, which can cause confusing results. Moreover, at higher pH values, the maleimide ring may open to form unreactive maleamic acid. The use of MAL-dPEG®24-NHS ester, product number QBD-10314, has been published in numerous scientific paper and patents. The following list highlights some of the more important uses of this product: extending the in vivo half-life of a therapeutic diabody; targeted delivery of a cancer drug via polylysine dendrimers; targeted delivery of drugs to the lungs; development of a blood purification device using magnetic nanoparticles; development of a targeted therapeutic system using superparamagnetic nanoparticles; improved transfection of tumor cells by PEGylated liposomes; development of immunosensors and biosensors; investigation of an aptamer using atomic force microscopy; attaching antibodies to atomic force microscopy probes; development of molecular pincers; improvement of a peptidic ligand used for capture and purification of IgM; and, surface coating of nanoparticles.
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品牌介绍

Click Chemistry Tools（CCT）公司位于美国亚利桑那州斯科茨代尔（Scottsdale,AZ）。自公司成立以来，一致致力于不断开发和扩展一系列连接产品。他们利用特别新的研究成果研发生产出新颖的交联和标记试剂。产品被广泛用于药物研发、癌症治疗以及各类诊断技术等。此外，CCT还可以提供个性化的定制产品，已满足不同用户的需求。目前CCT的产品线主要包括：Azides（Biotin-Azides）试剂、Bis-sulfone交联试剂、DBCO试剂、TCO试剂、Terminal Alkyne试剂、Tetrazine试剂、标记试剂盒以及分选用底物等。 Fluoroprobes公司位于美国亚利桑那州斯科茨代尔(Scottsdale, AZ)，自成立以来，一直致力于不断开发一系列的连接(linker)产品。利用特别新的研究成果研发生产出各类新颖的交联和标记试剂。其产品被广泛用于药物研发与筛选、疾病治疗方法和诊断技术等领域。此外，Fluoroprobes还可以根据客户的个性化需求提供各类定制连接产品。代表产品有Classic Fluorescent Dyes, AZDye, Cyanine Dyes, IR Dyes, MB dyes以及一些标记试剂盒等。 Quanta Biodesign公司位于美国中部的俄亥俄州，成立于1997年。也是专注于生产研发各类标记产品的品牌之一。其研发的产品与dPEG技术相结合，生产出他们独有的专利产品dPEG Building Blocks and Linkers，被广泛用于细胞治疗和分子诊断等研究领域。另外，还可为广大科研工作者提供多种化学修饰试剂以及传统Liner等。 目前上述三个品牌都已被被Vectorlabs收购并整合到Vectorlabs产品中

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