8-(2-[7-Nitro-4-benzofurazanyl]aminoethylthio]guanosine-3',5'-cyclic monophosphate sodium salt

8-NBD-cGMP is a fluorescent analog of cyclic guanosine monophosphate and a potent, membrane-permeable, fluorescent activator of cGMP-dependent protein kinase isozymes I α and I β. 8-NBD-cGMP is barely fluorescent in aqueous solution but fluoresces strongly in hydrophobic environments such as hydrophobic protein binding sites[1]

[1] Schmidpeter, et al. Ligand binding and activation properties of the purified bacterial cyclic nucleotide–gated channel SthK. Journal of General Physiology 150.6 (2018): 821-834. DOI:10.1085/jgp.201812023