although pertussis toxin has no significant homology to other adp-ribosylating toxins such as diphtheria toxin and pseudomonas aeruginosa exotoxin a , the results presented in this paper show that , as for diphtheria toxin and exotoxin a , tryptophan and glutamic acid residues are essential for the enzymatic activities of pertussis toxin .
C0040549
toxins
C0015309
exotoxin