Islet-activating protein, pertussis toxin: a probe for functions of the inhibitory guanine nucleotide regulatory component of adenylate cyclase

Abstract

The guanine nucleotide binding regulatory proteins (N) play an important role in communication between membrane receptors and the adenylate cyclase catalytic unit. One (N s) of the nucleotide regulatory proteins is involved in the activation, while the other (N i) is involved in the inhibition of adenylate cyclase. Islet-activating protein (IAP), pertussis toxin, catalyses the transfer of the ADP-ribose moiety of NAD to the active subunit ( M r = 41 00) of N u resulting in a complete loss of the N i functions. IAP will be useful as a tool for further studies of the transmembrane signal transduction mechanism.