General description

Product is not activated. If activation is required, see Kaslow, et al., for suggested conditions.

Physical form

Lyophilized powder containing sodium chloride and sodium phosphate buffer salts

Application

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.

Biochem/physiol Actions

Pertussis toxin catalyzes the ADP-ribosylation of the α subunits of the heterotrimeric guanine nucleotide regulatory proteins G_i, G_o, and G_t. This prevents the G protein heterotrimers from interacting with receptors, thus blocking their coupling and activation. Since the G_α subunits remain in their GDP-bound, inactive state, they are unable to inactivate adenylyl cyclase or open K⁺ channels.