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 quite 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 Bioassays offers a line of Europium-cryptate and XL-665 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 reproducibility
Product Specifications:
Streptavidins
Streptavidin is available labeled with either Europium-Cryptate or XL665. Cisbio Bioassays offers two XL-665 streptavidin
conjugates: Streptavidin XL665 and Streptavidin-XLent!.
Streptavidin-XLent! is a high grade streptavidin-XL665 conjugate in which the coupling conditions have been optimized to yield a conjugate with enhanced performance 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
Biotin
Biotinylation of molecules is a very straightforward, easy process and can be used with nucleic acids, proteins
and other chemical biomolecules. Cisbio Bioassays's toolbox reagent product line includes biotin-labeled
Europium-Cryptate which retains functionality of both the Europium fluorophore and stable binding to
streptavidin. This high quality reagent complements our other toolbox reagents to provide complete assay
development flexibility.
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: Various concentrations of Streptavidin-XLent! and competitor conjugates were used in an HTRF tyrosine kinase assay.
Assay Performance:
StreptavidinXLent! 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 StreptavidinXLent! for an EGFR tyrosine kinase assay. Over 25% less enzyme was required using StreptavidinXLent! to produce identical assay signals. This improved assay performance can increase assay sensitivity as well as the added benefit of reducing enzyme consumption which is extremely beneficial 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 active moiety per vial is also provided. In practice, the active moiety amount 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 Conjugates:
| Description | Quantity* | Active Moiety/vial | Cat no. | Product Insert |
| Streptavidin K | 5,000 tests | 40 µg | 610SAKLA | |
| Streptavidin K | 20,000 tests | 160 µg | 610SAKLB | |
| Biotin K | 5,000 tests | 0.5 µg | 61BTNKLA | — |
| Biotin K | 20,000 tests | 2 µg | 61BTNKLB | — |
XL665 Conjugates:
| Description | Quantity* | Active Moiety/vial | Cat no. | Product Insert |
| 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 | |
| WGA XL665 | 5,000 tests | 100 µg | 61WGAXLA ** | — |
| WGA XL665 | 20,000 tests | 400 µg | 61WGAXLB ** | — |
| ConA XL665 | 5,000 tests | N.D. | 61CNAXLA ** | — |
| ConA XL665 | 20,000 tests | N.D. | 61CNAXLB ** | — |
| *based on 20 µl assay volume | ||||
| **upon request | ||||
For more information or To Place an Order:
U.S. and Canada
1-888-963-4567
Europe and other countries
+33(0)466 796 705
Japan
+81-3-5510-2932
