Diphtheria toxin CRM197 mutant from C. diphtheriae is an inactive and non-toxic version of diphtheria toxin (Item No. 19657). It contains a single base change in the structural gene resulting in the substitution of glutamic acid for glycine which blocks ADP-ribosylation.1 Diphtheria toxin CRM197 mutant has no enzymatic activity but is immunologically indistinguishable from diphtheria toxin. Formulations containing diphtheria toxin CRM197 mutant have been used as carriers of conjugated polysaccharides in the development of vaccines against encapsulated bacterial pathogens.2Technical InformationPurity90% (estimated by SDS-PAGE)FormulationEAch vial, when reconstituted to 0.25 ml with water, contains 500 ug of diphtheria toxin CRM197 mutant in 0.01 M sodium phosphate with 5% lactose at pH 7.4