guanosine-triphosphate and gramine

The adenylate cyclase of the sea urchin egg is stimulated by dopamine in the presence of GTP. The enzyme activity is strongly enhanced when Gpp (NH)p is substituted for GTP, or after cholera toxin treatment. Gramine, an indolamine derivative, brings about non-competitive inhibition of the dopamine-stimulated adenylate cyclase activity. Pertussis toxin causes an attenuation of the gramine-induced inhibition of adenylate cyclase. These results show that dopamine and indolamine derivatives partecipate in the regulation of the adenylate cyclase activity of the sea urchin egg.

Topics: Adenosine Diphosphate Ribose; Adenylate Cyclase Toxin; Adenylyl Cyclases; Alkaloids; Animals; Cholera Toxin; Dopamine; Dose-Response Relationship, Drug; Guanosine Triphosphate; Guanylyl Imidodiphosphate; Indole Alkaloids; Pertussis Toxin; Sea Urchins; Virulence Factors, Bordetella