Figure 6

Inhibition of adenylyl cyclase. Recombinant adenylyl cyclase type V in insect cell membranes (10 g protein) was reconstituted with GTPS-activated myristoylated G_i to give the indicated final concentrations in the presence of 0.1 nM GTPS-bound native G_s (filled squares) or 20 nM GTPS-bound recombinant G_s (open squares). Please note, we determined the inhibitory action of myristoylated G_i at comparable levels of adenylyl cyclase pre-stimulated activity by using only 1/200 the amount of Gly²-palmitoylated than non-palmitoylated G_s. Pre-stimulated adenylyl cyclase activity in the absence of G_i (100% activity) was 3.8 nmol/min/mg protein for recombinant G_s and 4.2 nmol/min/mg protein for native G_s. Values are representative of one experiment out of three similar assays, mean SEM of duplicates was below 1%.