Abstract
ATP activates guanylate cyclase in cells of Dictyostelium discoideum . The K 0.5 for ATP activation is about 50 μM and saturates at about 0.3 mM ATP. Guanylate cyclase activity in crude extracts of D. discoideum shows Michaelian kinetics with a Km of about 1.0 mM GTP and V max of about 30 pmoles cyclic GMP/min/10 6 cells. In the presence of 0.3 mM ATP the enzyme kinetics is also Michaelian, the Km is lowered to about 0.2 mM GTP and the V max remains unchanged. Neither adenylyl-imidodiphosphate nor adenylyl (β,γ-methylene) diphosphonate can substitute ATP as activator of guanylate cyclase. The polyene antibiotic filipin inhibits basal guanylate cyclase activity while ATP activation is not affected.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
