GUANOSINE 5'-TRIPHOSPHATE REQUIREMENT FOR ACTIVATION OF ADENYLATE-CYCLASE BY SEROTONIN IN A SOMATIC-CELL HYBRID

Activation of adenylate cyclase [ATP: pyrophosphate-lyase (cyclising); EC 4.6.1.1] by serotonin in the NCB-20 mouse neuro-blastoma x foetal Chinese hamster brain hybrid cell line has been shown to require GTP. GTP increases slightly in the initial rate of cyclic AMP synthesis, and serotonin further increases the GTP-dependent increases in enzyme activity. In the presence of a saturating concentration of serotonin (10 μm), half-maximum activation of adenylate cyclase is produced by 0.1 μM GTP. © 1979.