| Source: |
Escherichia coli |
| Molecular Weight: |
Approximately 11.6 kDa, a single non-glycosylated polypeptide chain containing 103 amino acids. |
| AA Sequence: |
TPQNITDLCA EYHNTQIYTL NDKIFSYTES LAGKREMAII TFKNGAIFQV EVPGSQHIDS QKKAIERMKD TLRIAYLTEA KVEKLCVWNN KTPHAIAAIS MAN |
| Purity: |
> 98% by SDS-PAGE and HPLC analyses. |
| Physical Appearance: |
Sterile colorless liquid. |
| Formulation: |
Supplied as a 0.2 μm filtered solution in 5 mM PB, pH7.0, 75 mM NaCl, with 50% glycerol. |
| Endotoxin: |
Less than 0.1 EU/µg of rCTB as determined by LAL method. |
| Stability & Storage: |
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.- 6 months from date of receipt, -20 to -70°C as supplied.- 3 months, -20 to -70°C under sterile conditions after opening. |
| Background: |
Cholera toxin, produced by Vibrio cholerae, induces severe watery diarrhea characteristic of cholera infection. It is an oligomeric complex with six protein subunits: a single A subunit (enzymatic) and five B subunits (receptor binding), collectively known as AB5. Each B subunit, weighing 11 kDa, forms a ring structure that binds receptors, while the A subunit (28 kDa) has two segments. CTA1, a globular enzyme, ADP-ribosylates G proteins, while CTA2, an extended alpha helix, fits into the central pore of the B subunit ring. This toxin's structure, mechanism, and sequence resemble that of heat-labile enterotoxin from certain Escherichia coli strains. |
