adenylate cyclase activity in bovine retina was stimulated approximately 50 % by guanosine 5'-triphosphate ( gtp ) , but the nonhydrolyzable gtp analogue , guanosine-5'- ( beta , gamma-imido ) triphosphate ( gpp ( nh ) p ) , was able to activate the enzyme nearly 5-fold .
C0018353
gtp
C0018366
gpp ( nh ) p