Effects of GTP,GDP[βS] and glucose on adenylate cyclase activity of E. coli B

Abstract
Adenylate cyclase activity was measured in suspensions of E. coli B, rendered permeable with toluene. The enzyme was activated in a dose‐dependent manner by GTP and by its non‐hydrolysable analogue, GTP[γS]. In contrast, incubation with GDP[βS], a non‐phosphorylatable analogue of GDP, caused a dose‐related inhibition of adenylate cyclase; this was partially overcome by addition of GTP. GTP did not relieve, and GDP[βS] augmented, the non‐competitive and dose‐related inhibition of E.coli adenylate cyclase by glucose.