Toxin B, Clostridium difficile

Toxicity: Irritant (B)

A high molecular weight glucosyltransferase that inhibits small GTPases, such as Rho, Rac, and Cdc42, by glucosylation of a threonine residue.

A high molecular weight glucosyltransferase that inhibits small GTPases, such as Rho, Rac, and Cdc42, by glucosylation of a threonine residue. This results in the shutdown of signal transduction cascades, leading to depolymerization of the cytoskeleton, gene transcription of a number of stress-activated protein kinases (SAPKs), and a decrease in the synthesis of phosphatidylinositiol 4,5-bisphosphate. May also block serotonin release, and stimulate the production of phospholipases C and D. Due to its ability to affect depolymerization of the cytoskeleton, toxin B has been shown to inhibit biphasic muscle contraction. Unlike Exoenzyme C3 (Cat. No. 341208), this toxin does not require assistance to permeabilize cells.

major band at >200 kDa

Cytotoxic as determined in a cell rounding assay using human foreskin cells.

Primary Target
Small GTPases, such as Rho, Rac, and Cdc42

Product does not compete with ATP.

Mackay, D.J. and Hall, A. 1998. J. Biol. Chem. 273, 20685.
Prepens, U., et al. 1996. J. Biol. Chem. 271, 7324.
Schmidt, M., et al. 1996. Eur. J. Biochem. 240, 707.
Wilkins, T.D. and Lyerly, D.M. 1996. Trends Microbiol. 4, 49.

Lyophilized from 50 mM Tris, 50 mM NaCl, 0.1% trehalose, pH 7.5.

Following reconstitution, refrigerate (4°C). Stock solutions are stable for up to 2 weeks at 4°C. Toxin B activity will decrease after 2 weeks at 4°C following reconstitution.

Please see vial label for lot-specific reconstitution volume.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany