Jackson Immuno Research Inc.
specializing in secondary antibodies and conjugates

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Steptavidin, a bacterial protein isolated from Streptomyces avidinii, is similar to egg-white avidin in its ability to bind biotin, and has been used as a replacement for egg-white avidin because of its more favorable chemical properties.

Conjugates of streptavidin are recommended for use with Biotin-SP-conjugated antibodies and Biotin-SP-conjugated ChromPure proteins.
Physical State: Freeze-dried solid

Storage and Rehydration: Store freeze-dried solid at 2-8°C. Rehydrate with the indicated volume of dH2O and centrifuge if not clear. Prepare working dilution on day of use. Product is stable for about 6 weeks at 2-8°C as an undiluted liquid.
Extended Storage after Rehydration: Aliquot and freeze at -70°C or below. Avoid repeated freezing and thawing. Alternatively, add an equal volume of glycerol (ACS grade or better) for a final concentration of 50%, and store at -20°C as a liquid.
Expiration date: one year from date of rehydration. The expiration date may be extended if test results are acceptable for the intended use.


Buffer: 0.01M Sodium Phosphate, 0.25M NaCl, pH 7.6
Stabilizer: 15 mg/ml Bovine Serum Albumin (IgG-Free, Protease-Free)
Preservative: 0.05% Sodium Azide

Suggested Working Concentration or Dilution Range:

Western Blot:- 2-5 µg / ml
Histo-/Cyto-Chemistry:- 2-5 µg / ml

Dilution factors are presented in the form of a range because the optimal dilution is a function of many factors, such as antigen density, permeability, etc. The actual dilution used must be determined empirically.

Rhodamine Red™-X (RRX)

Amax: 570 Emax: 590nm

RRX (Rhodamine Red-X) conjugates have a peak of excitation at 570 nm and a peak of emission at 590 nm. Although TRITC has been used traditionally with FITC for double labeling, better color separation is achieved by using RRX or Alexa Fluor® 594. Rhodamine Red-X is particularly useful for 3- and 4-color labeling with DyLight 405, Alexa Fluor® 488, and Alexa Fluor® 647 by using a confocal microscope equipped with a 405 nm laser and a krypton/argon laser. Fluorescence from RRX lies about midway between that of Alexa Fluor® 488 and Alexa Fluor® 647, and it shows little overlap with either dye. The krypton-argon laser emits lines at 488 nm, 568 nm, and 647 nm, which are optimal for exciting Alexa Fluor® 488, RRX, and Alexa Fluor® 647, respectively. By adding a 405 nm laser and a 420 nm emission filter, 4-color labeling is possible using DyLight 405-conjugated secondary antibodies from JIR (Figure 5). The separation between all four dyes is perfect for 4-color labeling, and all four dyes are very bright.

This product is for IN VITRO RESEARCH USE ONLY. It is not a medical device and it is not intended for diagnostic or therapeutic purposes.

Rhodamine Red-X is a trademark of Molecular Probes, Inc. Jackson ImmunoResearch is licensed by Molecular Probes, Inc. to manufacture and sell conjugates of Rhodamine Red-X reactive dye.

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