Adenosine-3’,5’-cyclic Monophosphothioate, Rp-Isomer . sodium salt

Rp-cAMPS . Na, cAMPS . Na, Rp-Isomer

White to off-white powder. Please keep in mind that equal amounts of the compound may look different in volume depending on humidity. Rp-cAMPS is hygroscopic and tends to form a transparent film on the bottom of the tube.

73208-40-9

PKA

Inhibitor

C₁₀H₁₁N₅O₅PS . Na

Determined by MS and UV.

344.3 . 23.0

≥99% (HPLC) (low adenosine, cAMP and Sp-cAMPS content)

Soluble in water or aqueous buffers, DMSO, Methanol.

Since even minor impurities of cyclic AMP or the agonistic diastereomer Sp-cAMPS (0.2%) can already activate protein kinase A and compete with the antagonistic effect of the Rp- isomer, it is imperative to work with a strictly pure compound, especially concerning cyclic nucleotide contaminants. Cyclic AMP interference is not so important when working with cell cultures, since cAMP itself has very low membrane permeability and, in addition, would be metabolized immediately by both intracellular and external serum cyclic nucleotide-dependent phosphodiesterases.
Traces of the activator Sp-cAMPS, however, are fatal since it effectively competes with Rp-cAMPS and is only extremely slowly degraded by PDE. Another reason also demands for a pure reagent: Some cyclic AMP binding proteins other than kinases, such as some cyclic nucleotide-gated ion channels or the CAP protein, are activated by Rp-cAMPS. Thus, pure Rp-cAMPS can distinguish between protein kinase A and these receptors, but a contaminated reagent will yield misinformation.
This Rp-cAMPS is strictly checked for absence of activators such as Sp-cAMPS or cyclic AMP (< 0.05% when packed). Analysis of Rp-cAMPS from other sources, however, showed that this is not common practice.