HTRF® Affinity System Reagents
High Quality Streptavidins, Biotins & Lectins
The streptavidin-biotin reaction is by far one of the most frequently used affinity systems.Streptavidin-biotin binding is rapid and relatively stable making it an ideal choice for use in a variety of assays such as enzyme assays, protein-protein binding assays and molecular biology assays. Cisbio offers a line of HTRF Europium and Lumi4®-Terbium-Cryptate, XL665, and d2 congugated affinity system reagents including streptavidins, biotins and lectins to provide increased ease and flexibility in HTRF assay development.
- High-grade streptavidins
- Resistant to most buffer conditions and additives (e.g. DMSO, pH, chelators, ionic strength)
- Lyophilized packaging for easy handling and long term storage
- Proven batch-to-batch consistency
Product Specifications:
Streptavidins
Streptavidin is available labeled either with Europium or with Lumi4®-Terbium Cryptate donors, or with XL665 or d2 acceptors. Cisbio Bioassays offers two XL-665 streptavidin conjugates: Streptavidin XL665 and Streptavidin-XLent!.
Streptavidin-XLent! is a high grade streptavidin-XL665 conjugate for which the coupling conditions have been optimized to yield a conjugate with enhanced performances for some assays, particularly those requiring high sensitivity. When compared to competitor SA-APC conjugates, Streptavidin-XLent! shows overall superior performance (figure 1). Streptavidin-XLent! features include:
- Improved signal to noise ratio
- Higher performance
- Increased sensitivity
- Long term stability
Lectins
Two lectins, concanavalin A (Con A) and wheat germ agglutinin (WGA) are available as XL665 conjugates. Their specificity for simple or more complex sugars has enabled the development of several assays in the area of ligand-receptor interactions, which previously had no specific means of receptor detection.
Figure 1: To compare Streptavidin-XLent! with other commercially available conjugates, HTRF reagents (Europium-Cryptate PT66 and Streptavidin-XLent!) and conjugates from two other suppliers, were used in an HTRF tyrosine kinase assay. Our data revealed that for all concentrations tested, streptavidin-XLent! exhibited better performances.
Assay Performance:
Streptavidin-XLent! produces an average signal increase of 40% for a variety of assays. Figure 2 shows the results of a side-by-side comparison of SA-XL665 and Streptavidin-XLent! for an EGFR tyrosine kinase assay. Over 25% less enzyme was required when using streptavidin-XLent! to produce identical assay signals. Not only does assay performance include increase sensitivity, but streptavidin-XLent! also means lower enzyme consumption - a key consideration when quantities of the enzyme are limited or cost prohibitive.
Figure 2: Increasing quantities of EGFR were incubated with biotinylated polyGAT (50 nM). The enzymatic reaction was stopped using EDTA following a 20 minute incubation. Europium-labeled PT66 (20 ng/well) and Streptavidin-XL665 (50 nM) or StreptavidinXLent! (50 nM) were added. HTRF® signal was detected following a 20 minute incubation.
Ordering Info:
Reagents are sold by the number of tests (384-well, 20 µl reactions). Antibodies conjugated to XL665 are supplied on the basis of 20ng of antibody per well. The amount of active moiety per vial is also provided (as well as the number of tracers per moiety - see the product description sheet). In practice, the amount of active moiety is generally preferred to that of total conjugate as a basis for calculating assay development.
For more information about using HTRF toolbox reagents, click here.
Affinity System Toolbox Reagents:
Europium(K) and Lumi4®-Terbium(Tb) Cryptate Conjugates:
| Description | Quantity* | Active Moiety/vial | Cat no. | Product Insert | MSDS |
| Streptavidin K | 5,000 tests | 9 µg | 610SAKLA | ||
| Streptavidin K | 20,000 tests | 36 µg | 610SAKLB | ||
| Streptavidin Tb | 5,000 tests | 4 µg | 610SATLA | ||
| Streptavidin Tb | 20,000 tests | 16 µg | 610SATLB |
XL665 and d2 Conjugates:
| Description | Quantity* | Active Moiety/vial | Cat no. | Product Insert | MSDS |
| Streptavidin XL665 | 5,000 tests | 250 µg | 610SAXLA | ||
| Streptavidin XL665 | 20,000 tests | 1,000 µg | 610SAXLB | ||
| Streptavidin XLent! | 5,000 tests | 250 µg | 611SAXLA | ||
| Streptavidin XLent! | 20,000 tests | 1,000 µg | 611SAXLB | ||
| Streptavidin d2 | 5,000 tests | 250 µg | 610SADAA | ||
| Streptavidin d2 | 20,000 tests | 1,000 µg | 610SADAB | ||
| WGA XL665 | 5,000 tests | 100 µg | 61WGAXAA ** | — | |
| WGA XL665 | 20,000 tests | 400 µg | 61WGAXAB ** | — | |
| *based on 20 µl assay volume | |||||
| **upon request | |||||
For more information or To Place an Order:
