Isolation and characterization of PDE-I and II, the inhibitors of cyclic adenosine-3',5'-monophosphate phosphodiesterase.

In the screening for inhibitors of cyclic adenosine-3', 5'-monophosphate phosphodiesterase, two compounds, PDE-I (C18H13N3O5) and PDE-II (C14H14N2O5), were isolated from culture filtrates of a Streptomyces. Concentrations for 50% inhibitions of PDE-I and PDE-II against the high Km enzyme were 15 μM and 13 μM, and those against the low Km enzyme were 65 μM and 130 μM, respectively. Production, isolation and characterization of these compounds are described.