Glucosyltransferase Activity of Toxin

Clostridium difficile Toxin B as a Probe for Rho GTPoses Pl61 

In cell-free systems (recombinant GTPases or cell lysates), both toxins exhibit their enzymic effects only at a concentration 10-100 times higher than that applied to intact cells. This difference in concentration may be due to failure in toxin activation, which most likely occurs when the toxins enter the cell by receptor-mediated endocyto-sis. The same is true when the toxins are microinjected, thereby bypassing the entry (and activation) mechanism. 

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