2',3'-Cyclic-Nucleotide PhosphodiesterasesPhosphoric Diester HydrolasesPhosphodiesterase InhibitorsNucleotidasesSulfonesPurinesProtease Inhibitors1-Methyl-3-isobutylxanthine3',5'-Cyclic-AMP PhosphodiesterasesPhosphodiesterase 5 InhibitorsRolipram3',5'-Cyclic-GMP PhosphodiesterasesHIV Protease InhibitorsPurinonesCyclic Nucleotide Phosphodiesterases, Type 54-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinonePiperazinesCyclic AMPCyclic Nucleotide Phosphodiesterases, Type 4Cyclic GMPTheophyllinePhosphodiesterase 3 InhibitorsErectile DysfunctionMilrinonePhosphodiesterase 4 InhibitorsCyclic Nucleotide Phosphodiesterases, Type 3PapaverineSerine Proteinase InhibitorsHIV ProteasePyrrolidinonesPhosphodiesterase ICyclic Nucleotide Phosphodiesterases, Type 1Vasodilator AgentsColforsinPentoxifyllinePenile ErectionBucladesineMolecular Sequence DataPeptide HydrolasesKineticsSerine EndopeptidasesXanthinesPyridazines8-Bromo Cyclic Adenosine MonophosphateNucleotides, CyclicDose-Response Relationship, DrugAmino Acid SequenceAdenylate CyclaseEndopeptidasesCysteine EndopeptidasesCells, CulturedSecretory Leukocyte Peptidase InhibitorIsoproterenolPyrimidinonesSaquinavirRitonavirIndinavirCysteine Proteinase InhibitorsHypertension, PulmonaryTime FactorsTrypsin InhibitorsEnoximoneProteinase Inhibitory Proteins, SecretorySerpinsEnzyme ActivationNelfinavirCysteine ProteasesVinca AlkaloidsNitric OxideCalciumCell LineCyclic Nucleotide Phosphodiesterases, Type 2PenisHydrolysisProteasome Endopeptidase ComplexSignal TransductionAmrinoneCyclic AMP-Dependent Protein KinasesAlprostadilCyclic Nucleotide Phosphodiesterases, Type 6Guanylate CyclaseAminophyllineTriazinesCattleProtease NexinsBufo bufoEnzyme InhibitorsSubstrate SpecificityCyclic GMP-Dependent Protein KinasesCarbamatesSulfonamidesProteolysisMutationPhotoreceptor CellsVentricular Dysfunction, Leftalpha 1-AntitrypsinDibutyryl Cyclic GMPRNA, MessengerRats, Sprague-DawleyLopinavir