Inhibition of adenylate cyclase by a membrane protein from rat cerebrum

The inhibitor protein of adenylate cyclase was partially purified from detergent-extract of rat brain. The inhibition occurred without lag phase. Calmodulin, GTP, guanyl 5'-yl imidodiphosphate (Gpp (NH) p) and forskolin did not change the inhibition, but activities stimulated by NaF or Mn2+ were more resistant for the inhibition. The inhibitor might include an essential sulfhydryl group.