The toxin is released from B. pertussis in an inactive form. When the pertussis toxin B oligomer binds to the cell membrane, the S1 subunit of its A protomer becomes activated, perhaps through the action of glutathione and ATP. A protocol for activating pertussis toxin in vitro is given by Kaslow, et al.
Product is not activated. If activation is required, see Kaslow, et al., for suggested conditions.
Pertussis toxin catalyzes the ADP-ribosylation of the α subunits of the heterotrimeric guanine nucleotide regulatory proteins Gi, Go, and Gt. This prevents the G protein heterotrimers from interacting with receptors, thus blocking their coupling and activation. Since the Gα subunits remain in their GDP-bound, inactive state, they are unable to inactivate adenylyl cyclase or open K+ channels.
Purify the toxin by stepwise elution from 3 columns comprising Blue Sepharose, Phenyl Sepharose and hydroxylapatite, and the purity is checked by SDS-PAGE. [Svoboda et al. Anal Biochem 159 402 1986, Biochemistry 21 5516 1982, Biochem J 83 295 1978.]
