Figure 4. Activation of Drosophila melanogaster guanylyl cyclases with NO donors and BAY 41-2272. COS-7 cells were transiently transfected with the subunits shown and extracts assayed for guanylyl cyclase activity in the presence of 4mM Mg2+ and the absence or presence of different concentrations of the NO donors, S-nitroso-N-acetylpenicillamine (SNAP) (A), NOC-12 (B) or DEA-NONOate (C) or the NO-independent guanylyl cyclase activator, BAY 41-2272 (D). Each point represents mean ± SEM. of 2–3 determinations.