Since 1978, List Labs products are unsurpassed in quality, consistency, and reliability for the success of your research and development projects! Clostridium difficile is the causative agent of antibiotic-associated diarrhea and pseudomembranous colitis. It produces two major exotoxins (Toxin A and Toxin B), which are the prototypes of the family of large clostridial cytotoxins. Clostridium difficile A and B are high molecular weight glucosyltransferases that inhibit members of the Rho family of GTPases. Toxin A, referred to as an enterotoxin, has a molecular weight of 300 kDa and an isoelectric point, pl, of 5.3. Toxin B, known as a cytotoxin, has a molecular weight of 270 kDa and a pl of 4.1. By inhibition of signal transduction cascades, Toxin A and Toxin B are able to block downstream responses. Toxin B may block serotonin release, as well as stimulate production of phospholipases C and D.