生物标记素蛋白Biotinylated Protein

Products
 

PrecisionAvi Series

An exclusive collection of ready-to-use Avitag^TM biotinylated proteins
 

The products in this series are exclusively produced using the Avitag^TM technology. Briefly, a unique 15 amino acid peptide, the Avi tag, is introduced into the recombinant protein during expression vector construction. The single lysine residue in the Avi tag is enzymatically biotinylated by the E. Coli biotin ligase BirA.

This single-point enzymatic labeling technique brings many advantages for commonly used binding assays. The biotinylation happens on the lysine residue of Avi tag, and therefore does NOT interfere with the target protein’s natural binding activities. In addition, when immobilized on an avidin-coated surface, the protein orientation is uniform because the position of the Avi tag in the protein is precisely controlled.
 

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UltraLys Series
 

A unique series of chemically labeled biotinylated proteins with ultra sensitivity
 

The products in this series are produced using our in-house developed chemical labeling approach. The primary amines in the side chains of lysine residues and the N-terminus of protein are conjugated with biotins.

Chemical labeling usually results in multiple biotin attachment on a single protein molecule, which could potentially lead to higher detection sensitivity.
 

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High Quality Authentic Human Proteins

The production of our recombinant proteins including the biotinylated proteins is carried out using our proprietary HEKMax® expression platform. As expression hosts, the human HEK293 cells have a variety of advantages compared to other cell types as summarized in the table below. Most importantly, the proteins retain their authentic post-translational processing, which often translates into high bioactivity and stability.

High Bioactivity & Detection Sensitivity

The bioactivity of biotinylated proteins is determined both by the structure of the protein itself, and by the way how biotinylation is performed. For every single protein, we test multiple options of tags and biotinylation methods, and evaluate the products in a variety of binding assays. Only those with the best performance are selected for production. Figure 1 is an example of our internal evaluation experiments:

Our biotinylated proteins demonstrate high bioactivity and superb detection sensitivity. In the following Fig. 2, Biotinylated FcRn / FCGRT & B2M (Cat.# FCM-H82W4) coupled to SA coated sensor chip can bind Herceptin with an affinity constant of 2.24 μM as determined in a SPR assay. And in Fig. 3, when used in a functional ELISA, the biotinylated VEGF165 (Cat# VE5-H8210) can bind to immobilized rhVEGFR2 with a EC50 of 0.5-5 ng/mL.

 

Fig. 2 Biotinylated Human FcRn / FCGRT & B2M, Avi Tag (Avitag™) (Cat.# FCM-H82W4) coupled to SA coated sensor chip can bind Herceptin with an affinity constant of 2.24 μM as determined in a SPR assay (Biacore 2000). The data is generally provided by Biaffin GmbH &Co KG, Germany.


 

Fig. 3 The ELISA assay result of the biotinylated VEGF165 (Cat# VE5-H8210) which bind to immobilized rhVEGFR2.
 

Low Batch-to-Batch Variation

We routinely apply rigorous quality control measures to ensure consistent performance of our products. Newly produced products are subjected to side-by-side comparison with our internal standard in a variety of assays. Only those within an acceptable margin of difference are allowed to be released. As demonstrated in Fig. 4, both EGFR-biotin batches show very similar KD values in a range between 104-112nM and are indistinguishable within the precision of the assay.
 

Fig. 4 Two lots of EGFR-biotin (Cat# EGR-H82E7) were immobilized on Sensor Chip SA in an SPR analysis to determine their binding affinity against EGF. Gradient concentration of EGF (ACRO’s product, EGF Cat# EGF-H4114  ) was injected over the surface. Please note that the KD values from both experiments are highly consistent with each other. The SPR analysis is performed by Biaffin GmbH & Co KG, Germany.

 

Additionally, we also tested their performance in a standard ELISA analysis against Centuximab and 0.2µg/well Centuximab was used to coat the plate(Fig. 5).

 

Fig. 5 The same two lots of EGFR-biotin (Cat # EGR-H82E7) were used is a standard ELISA assay, Please note that the results were consistent between these two batches.
 

Limited Use License

The Biotin AviTag technology is covered by U.S. Pat. No: 5,874,239 and includes any and all materials, methods, kits and related derivatives claimed by this patent. The purchase of the Acrosbiosystems’s Avitag^TM proteins confers to the purchaser the limited right to use the Avitag^TM technology for non-commercial, or research use, or for purposes of evaluating the Avitag^TM technology.

Commercial use of the Avitag^TM technology to manufacture a commercial product, or use of the Avitag^TM technology to facilitate or advance research which will be applied to the development of a commercial product requires a license from Avidity, LLC. Examples of Commercial use include, but are not limited to biosensors, diagnostics, therapeutic applications, proximity assays, and drug screening assays.