Interaction of the catalytic subunit of protein kinase A with the lung type V cyclic GMP phosphodiesterase: modulation of non-catalytic binding sites.
We have previously demonstrated that the catalytic sub-unit of protein kinase A can catalyse a potent activation of partially purified Type V cyclic GMP-specific phosphodiesterase activity (Burns et al., 1992, Biochem. J. 283, 487-491). We now demonstrate that this phosphodiesterase most likely has a sub-unit mass of 90kDa, based upon 32P-cyclic GMP photo-affinity labelling, that activation of the phosphodiesterase does not require the prior binding of cyclic GMP to the phosphodiesterase, and that alkaline phosphatase can reverse the protein kinase A-dependent activation of phosphodiesterase activity. Zaprinast is a mixed inhibitor of non-activated cyclic GMP phosphodiesterase activity. However, inhibition of the protein kinase A-activated phosphodiesterase is competitive. These results suggest that protein kinase A can modulate the inhibitory effects of zaprinast via perturbations of a non-catalytic binding site.
Burns
F
F
Department of Physiology and Pharmacology, University of Strathclyde, Glasgow, Scotland.
Pyne
N J
NJ
D015106:3',5'-Cyclic-GMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D006152:Cyclic GMP / Q000378:metabolism / Q000494:pharmacology; D004789:Enzyme Activation; D006168:Guinea Pigs; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008168:Lung / Q000201:enzymology*; D046911:Macromolecular Substances; D011494:Protein Kinases / Q000378:metabolism*; D011688:Purinones / Q000494:pharmacology; D011719:Pyrazines / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D020889:Rolipram
D007527:Isoenzymes; D046911:Macromolecular Substances; D011688:Purinones; D011719:Pyrazines; D011760:Pyrrolidinones; C048350:5-(4-acetamidophenyl)pyrazin-2(1H)-one; D011494:Protein Kinases; D000469:Alkaline Phosphatase; D015106:3',5'-Cyclic-GMP Phosphodiesterases; C011145:zaprinast; D006152:Cyclic GMP; D020889:Rolipram