Table 2. Effect of different compounds on the enzymatic activity of recombinant T. cruzi PDEs.
Inhibition of TcrPDEB1 or B2 cAMP hydrolysis by various known cNMP PDE inhibitors were measured using conventional radioactive PDE assays. The results were also compared with published data for the T. brucei TbrPDEBs as well as for L. mexicana homogenates. A dash (–) indicates values that were not determined, and underlined numbers are from D'angelo et al. [18]. The results are the means±S.E.M. for three independent experiments. The cAMP concentration was 2 μM.
| IC50 (μM) | |||||
|---|---|---|---|---|---|
| Inhibitor | TbrPDEB2/TbPDE2B [12] | TbrPDEB1/TbPDE2C [13] | L. mexicana [39] | TcrPDEB2/TcPDE1 [18] | TcrPDEB1 |
| Dipyridamole | 27 | 14.6 | − | 15.0±2 17±4 | 11.3±2 |
| EHNA | >180 | − | − | 128±2 217±4 | >200 |
| Enoximone | >100 | − | − | >100 | >100 |
| cGMP | >200 | >100 | >1000 | >500 No inhibition | >500 |
| IBMX | >1000 | 1700 | 2000 | >300 >1000 | >300 |
| Papaverine | 304 | − | − | 104.8±3 111±17 | >500 |
| Pentoxifylline | >800 | − | − | >500 | >500 |
| Rolipram | >300 | − | 700 | >500 >500 | >500 |
| Zaprinast | >50 | − | 2800 | >300 | − |