[Pertussis toxin stimulates brain adenyl cyclase and induces ADP ribosylation of a 40,000 dalton membrane protein].

The adenylate cyclase activity of Rat brain synaptosomal membranes is strongly activated by forskolin. This study demonstrates: 1. That GTP or its analogs, when added to forskolin, decrease the enzyme stimulation by a factor of 40 to 60%; 2. That Pertussis toxin (TP), in the presence of NAD, ADP-ribosylates a single membrane protein of 40,000 dalton apparent molecular weight in a strictly concomitant manner. This Lubrol-soluble protein has a sedimentation coefficient of 3.6 and a Stokes radius of 6 nm. An immune serum against TP blocks the NAD-glycohydrolase activity of the toxin.