8-[φ-575]-2′-O-Me-cAMP

In 8-[φ-575]-2’-O-Me-cAMP the relatively small Pharos 575 dye is connected to position 8 of the heterocyclic nucleobase of cyclic AMP (cAMP) via a spacer. In addition, the ribose 2’-hydroxy group has been methylated.
8-[φ-575]-2’-O-Me-cAMP is a fluorescent analogue of cAMP with λ_exc 577 nm and λ_em 605 nm. The fluorophore can be excited e.g. by a Kr/Ar laser. Due to its high lipophilicity/membrane permeability and bright red fluorescence, 8-[φ-575]-2’-O-Me-cAMP is especially suitable for studies with intact cells. Since a free 2’-ribose hydroxy group in cAMP is essential for stimulation of cAMP-dependent protein kinase (PKA), the methylated structure of 8-[φ-575]-2’-O-Me-cAMP does not activate PKA, but is expected to be a selective stimulator of the exchange proteins directly activated by cAMP (Epac or cAMP-GEF).