We have been studying the mechanism by which light and nucleoside triphosphates activate the discmembrane phosphodiesterase (oligonucleate 5'-nucleotidohydrolase; EC 3.1.4.1) in frog rod outer segments. GTP is orders of magnitude more effective than ATP as a cofactor in the light-dependent activation step. GTP and the analogue guanylyl-imidodiphosphate function equally as allosteric activators ...

Reis (1) discovered 5’-nucleotidase in 1934. Shortly thereafter, Gulland and Jackson (2) showed its presence in venoms of many species of snake. Although several methods of separation of 5’-nucleotidase from phosphodiesterase of venom have been proposed (3-7), the available preparations of 5’-nucleotidase are still rather crude (8-10). Two reasons prompted us to purify venom 5’-nucleotidase. Fi...

Immunoblot and enzyme-activity analyses, using specific immunological probes, indicated that more than 80% of the total low-Km cAMP phosphodiesterase activity present in bovine and human platelets resided in a single phosphodiesterase isozyme. In the presence of protease inhibitors, the platelet enzyme has an apparent subunit size of 110 kDa and appears immunologically and structurally indistin...

To determine the presence of cone or rod cyclic GMP phosphodiesterase (EC 3.1.4.17) in the mammalian pineal, extracts from adult rat and bovine pineals were injected onto a Mono Q anion-exchange HPLC column and eluted with an NaCl linear gradient. Fractions were immunoadsorbed with monoclonal antibodies specific to rod and cone phosphodiesterases (ROS-1) and to calmodulin-phosphodiesterase comp...

We estimated nucleotide pyrophosphatase and phosphodiesterase I activities in human and rat organs and in body fluids from man and dog. The highest organ activities were found in epididymis, kidney, liver, and intestine. In body fluids, the activity was highest in seminal plasma, followed by intestinal lymph, serum, heart lymph, cerebrospinal fluid, milk, and urine. The ratio nucleotide pyropho...

Biofilm-related infections are a major contributor to human disease, and the capacity for surface attachment and biofilm formation are key attributes for the pathogenesis of microbes. Serratia marcescens type I fimbriae-dependent biofilms are coordinated by the adenylate cyclase, CyaA, and the cyclic 3',5'-adenosine monophosphate (cAMP)-cAMP receptor protein (CRP) complex. This study uses S. ma...

Avanafil is a medication that was recently approved by the US Food and Drug Administration for the management of erectile dysfunction. Avanafil is a new phosphodiesterase type 5 inhibitor similar to sildenafil and tadalafil. Avanafil was studied in over 1300 patients during clinical trials, including patients with diabetes mellitus and those who had undergone radical prostatectomy, and was foun...

Brain cytoplasmic cyclic 3':5'-nucleotide phosphodiesterase (EC 3.1.4.17) requires an endogenous Ca2+-binding protein for ful activity. We now show that lysophosphatidylcholine also effectively enhances activator-deficient phosphodiesterase activity. Stimulation by both ligands was immediate and reversible; both rendered the enzyme more thermally labile, decreased the energy of activation, and ...

Deoxyribonuclease II (Deoxyribonucleate 3’-nucleotidohydrolase, EC 3.1.4.6) was purified 1250-fold from bovine spleen. The specific activity of the final preparation was 408. It was free of phosphatase and alkaline ribonuclease, and almost free of nonspecific phosphodiesterase, acid ribonuclease, and adenosine triphosphatase. Chromatography on carboxymethyl cellulose prior to heating caused the...

The cyclic AMP and cyclic GMP phosphodiesterase activities present in flies of six mutant strains of the dunce gene and in the parent wild-type strains are characterized. All of the mutants exhibit aberrant cyclic AMP metabolism. The mutant strains dunceM14, dunceM11, and dunceML appear to be amorphic, because they completely lack the cAMP-specific phosphodiesterase normally present in adult fl...