Merck, SAE0069-500UG, Cholera Toxin B subunit

General description
The advantage of this product over the native CTXB is that it has no traces of Vibrio cholera, and no contamination of the highly toxic Cholera toxin A subunit. This product is expressed in human HEK 293 cells as a C-terminally his-tagged protein with a calculated molecular mass of 13 kDa (amino acids Thr22-Asn124).
The protein is recombinant, and therefore has no contamination of the highly toxic Cholera toxin A subunit.
Under non-reducing conditions, it migrates as pentamer of ~70 kDa, consistent with the pentamerization of CTXB.
Application
Cholera Toxin B subunit has been used:

• for macrophage stimulation and i.p. injection in a study to determine the endotoxin sensitivity of Caspase-4.
• in transganglionic and retrograde tract-tracing method combined with dual-immunofluorescence histochemistry of adult rat Vmes neuron cells.

Physical form
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4.
Preparation Note
When reconstituted with water to a final concentration of 1 mg of CTB per ml, the solution will contain 1X PBS
Analysis Note
Activity measured by ELISA using ganglioside GM1-coated multiwell plates, rabbit anti-Cholera toxin B subunit antibodies, and peroxidase-labeled goat anti-rabbit IgG as the secondary antibody. 50% saturation of binding was achieved with ≤1 μg of Cholera toxin B subunit per mL.