Polyoxotungstates as potent inhibitors for ecto-nucleotidases

The particular structural features of transition metal oxygen anion clusters cause a rapidly expanding scientific as well as practical interest for these compounds, e.g. applications in areas including catalysis, materials chemistry and biochemistry. In the past decade, especially polyoxometalates (POMs) based on V(V), Mo(VI) and W(VI) were found as attractive candidates for medical applications. Such polynuclear metal compounds show unique transport properties into cells, and may act as antiviral and antitumoral agents.
We want to report the enzyme inhibition behaviour of the polyoxotungstates [W₁₂O₃₉]^6- (1), [W₁₂PO₄₀]^3- (2), [Ti₂W₁₀PO₄₀]^7- (3), [TiW₁₁CoO₄₀]^8- (4), [Co₄(H₂O)₂(W₉PO₃₄)₂]^10- (5), and [NaSb₉W₂₁O₈₆]^18- (6) towards the ecto-nucleotidases NTPDase 1, 2 and 3.
The polyoxotungstates (3) and (4) have been characterised by single X-ray diffraction showing the typical Keggin structure.
All of the polyoxotungstates investigated are potent inhibitors of the NTPDases 1-3 with Ki values between 0.14 and 29 µM.