The distinct phosphodiesterase isoenzyme activities in guinea-pig lung were identified and characterised. We demonstrate that protein kinase A catalyses the activation of lung Type V cyclic GMP phosphodiesterase. This occurs via a marked change in the Vmax for cyclic GMP hydrolysis. The sensitivity of the activated PDE to inhibition by zaprinast is also markedly reduced (zaprinast inhibits in PDE activity via a mixed mechanism). We suggest that activation of the PDE by protein kinase A involves a mechanism that leads to alteration in the regulatory action of a non-catalytic cyclic GMP binding site.
|Number of pages||15|
|Journal||Agents and actions. Supplements|
|Publication status||Published - 1993|
- 3',5'-Cyclic-GMP Phosphodiesterases
- enzyme activation
- Guinea Pigs
- phosphoric diester hydrolases