Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.2 (guanylate cyclase)
 8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Furoxans (1,2,5-oxadiazole-2-oxides) are widely used in organic chemistry as intermediate compounds for the synthesis of various heterocycles. Despite the fact that some furoxans have been found to possess remarkable biological activities, up to now no systematic study on their mode of action has been reported. The aim of the present study was to investigate the molecular mode of the vasodilator action of furoxans. Furoxans, but not the corresponding furazans, concentration-dependently increased coronary flow in an isolated working rat heart preparation. This effect was blunted upon coinfusion with methylene blue. All tested furoxans were demonstrated to increase potently the activity of soluble guanylate cyclase. Enzyme stimulation was found to be mediated by the generation of nitric oxide (NO) following chemical reaction of the furoxans with sulfhydryl groups of low molecular weight thiols and proteins. Furoxans are thus prodrugs which increase the level of cyclic GMP via formation of NO and may therefore be classified as nitrovasodilators. Along with the generation of NO, nitrite and nitrate ions and S-nitrosothiols were formed. The rates of formation of these metabolites, however, did not appear to be related to enzyme stimulation. A tentative reaction scheme that fits the obtained experimental data is proposed. Recently reported cytotoxic, mutagenic, immunosuppressive and anticancer effects of furoxans are discussed in the light of their ability to release NO upon reaction with thiols.
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PMID:Thiol-mediated generation of nitric oxide accounts for the vasodilator action of furoxans. 135 72

The influence of artemisinin on the activity of human platelet soluble guanylyl cyclase was investigated. Artemisinin (0.1-100 microM) had no effect on the basal activity of the enzyme. Artemisinin inhibited in a concentration-dependent manner the sodium nitroprusside-induced activation of human platelet guanylyl cyclase with an IC(50) value 5.6 microM. Artemisinin (10 microM) also inhibited (by 71+/-4.0%) the activation of the enzyme by the thiol-dependent nitric oxide (NO) donor, the derivative of furoxan, 3,4-dicyano-1,2,5-oxadiazole 2-oxide (10 microM), but did not influence the stimulation of soluble guanylyl cyclase by protoporphyrin 1X. Inhibition of guanylyl cyclase activation by NO donors but not by protoporphyrin 1X represents a possible additional mechanism of the pharmacological action of this drug.
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PMID:Inhibition of nitric oxide-dependent activation of soluble guanylyl cyclase by the antimalarial drug, artemisinin. 1190 12