IBA Lifesciences GmbH products

Biotin stock solution for preparing a dissociation buffer when using the Strep-tag technology for cells (Fab-TACS/Nano-TACS, CD3/CD28 Streptamer, MHC I Streptamer) or exosomes (Fab-TACS for exosomes). Biotin addition causes the rapid dissociation of isolation reagents from the surface. Thus, fully functional and highly pure cells or exosomes are received.

10x Buffer CI is a 10x concentrated buffer suitable for cell isolation. It contains 10x PBS with 10 mM EDTA and 5% BSA.

CD81 Fab-Strep is a recombinantly expressed low affinity Fab fragment fused to a Twin-Strep-tag. Fab-Streps were developed for Traceless Affinity Cell Selection (Fab-TACS), which is based on our Strep-tag technology. Due to their low affinity for the target, an increase in avidity is required to ensure sufficient binding to the cell or exosome surface. Combining Fab-Streps with a Strep-Tactin^® backbone leads to the formation of complexes that stably bind to cells or alternatively, also to exosomes.

Anhydrotetracycline is a derivative of tetracycline and an efficient inducer of the tetracycline promoter present in E. coli expression vectors pASK-IBA and pASG-IBA. It does not exhibit antibiotic activity within our recommended concentrations.

Avidin is a tetrameric biotin binding protein (KD ~1 x 10^-14) extracted from egg white. It prevents biotin and biotinylated proteins from binding to Strep-Tactin  or Strep-Tactin XT, whereas binding of the Twin-Strep-tag and Strep-tagII is not influenced. Biotin and/or biotinylated proteins can potentially reduce the binding capacity of Strep-Tactin as well as Strep-Tactin XT and are present in cell lysates and cell culture media, especially from mammalian or insect cells. Thus, if Twin-Strep-tag and Strep-tag II fusion proteins from biotin-containing extracts or media are intended to be purified via Strep-Tactin or Strep-Tactin XT affinity chromatography, biotin has to be masked by addition of avidin prior to application onto the resin. Biotin Blocking Buffer (2-0501-002) for western blotting can be prepared by dissolving 2.5 mg/ml Avidin in PBS buffer.

Anhydrotetracycline is a derivative of tetracycline and an efficient inducer of the tetracycline promoter present in E. coli expression vectors pASK-IBA and pASG-IBA. It does not exhibit antibiotic activity within our recommended concentrations.

GFP-Twin-Strep-tag is a control proteins consisting of the green fluorescent protein (GFP) C-terminally tagged with the Twin-Strep-tag. It is suitable for test purifications, detections, and immobilizations with Strep-Tactin^® or Strep-Tactin XT.

BioLock is a ready-to-use biotin blocking solution which contains the tetrameric biotin binding protein avidin. BioLock prevents biotin and biotinylated proteins from binding to Strep-Tactin or Strep-Tactin XT, whereas binding of the Twin-Strep-tag and Strep-tagII is not influenced. Biotin and/or biotinylated proteins can possibly reduce the binding capacity of Strep-Tactin as well as Strep-Tactin XT and are present in cell lysates and cell culture media, especially from mammalian or insect cells. Thus, if Twin-Strep-tag and Strep-tag II fusion proteins from biotin-containing extracts or media are intended to be purified via Strep-Tactin or Strep-Tactin XT affinity chromatography, biotin has to be masked by addition of BioLock prior to application onto the resin.

Biotin is a water-soluble B-complex vitamin, also known as vitamin B7 or vitamin H. It binds to the biotin-binding pockets of streptavidin, Strep-Tactin^®, and Strep-Tactin XT with different affinities. As a result, it allows the efficient elution of Strep-tag II or Twin-Strep-tag  fusion proteins from Strep-Tactin XT, while maintaining the reusability of the resin. It can be used for preparation of Strep-Tactin XT elution buffer, Buffer BXT. In addition, biotin can be used for elution of biotinylated proteins from Strep-Tactin^®, where it binds irreversibly to the resin. Hence, Strep-Tactin^® cannot be regenerated in this kind of application.

Buffer BXT (10x) is a 10x concentrated Strep-Tactin XT elution buffer containing biotin. Biotin is a water-soluble B-complex vitamin, also known as vitamin B7 or vitamin H. It binds to Strep-Tactin XT with very high affinity, but reversibly, and thereby allows the efficient elution of Strep-tag II or Twin-Strep-tag  fusion proteins from the resin. Please note that Buffer BXT (10x) is not applicable for elution of Strep-tag II or Twin-Strep-tag fusion proteins from Strep-Tactin^®, since biotin irreversibly binds to these resins, and thus Strep-Tactin^® cannot be regenerated.