Biomaterial Database

[Thiol-dependent activation of guanylate cyclase by organic nitrates]. 1986

H Schröder, and E Noack

Organic nitrates produce their pharmacological effect by an intracellular stimulation of the enzyme guanylate cyclase (E. C. 4.6.1.2). We could show that the stimulatory effect of organic nitrates on the activity of guanylate cyclase is strongly dependent on the number of nitrate residues per molecule. The EC50 values found for the tetra-, tri- di-, and mononitrates differed from each other by the factor 4. In contrast to investigations carried out with the perfused isolated Langendorff heart there was no correlation between the lipophilicity of these substances and the EC50 in our guanylate cyclase preparation, as penetration of cell membranes is not required. Other authors have found that organic nitrates are able to activate the enzyme guanylate cyclase only in the presence of cysteine. There is general agreement in the literature that organic nitrates have to be cleaved before they become biologically active. During the transformation which takes place in the presence of cysteine or by means of enzymatic catalysis the nitric oxide radical is liberated as the essential stimulatory agent. We found a strict correlation between the liberation of nitric oxide from different organic nitrates (GTN, IMDN, IIDN, ISDN, IS-2-N, IS-5-N) and the degree of enzyme activation. The Ec50 values of the organic nitrates were calculated from the concentration response curves which were obtained with a guanylate cyclase preparation from rat liver in the presence of cysteine. The degradation of the organic nitrates was measured under the same conditions by means of HPLC. The amount of nitric oxide set free was calculated by using the velocity constants k of organic nitrate degradation.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D009566	Nitrates	Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.	Nitrate
D003545	Cysteine	A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.	Cysteine Hydrochloride,Half-Cystine,L-Cysteine,Zinc Cysteinate,Half Cystine,L Cysteine
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D005978	Glutathione	A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.	Reduced Glutathione,gamma-L-Glu-L-Cys-Gly,gamma-L-Glutamyl-L-Cysteinylglycine,Glutathione, Reduced,gamma L Glu L Cys Gly,gamma L Glutamyl L Cysteinylglycine
D006162	Guanylate Cyclase	An enzyme that catalyzes the conversion of GTP to 3',5'-cyclic GMP and pyrophosphate. It also acts on ITP and dGTP. (From Enzyme Nomenclature, 1992) EC 4.6.1.2.	Guanyl Cyclase,Deoxyguanylate Cyclase,Guanylyl Cyclase,Inosinate Cyclase,Cyclase, Deoxyguanylate,Cyclase, Guanyl,Cyclase, Guanylate,Cyclase, Guanylyl,Cyclase, Inosinate
D000111	Acetylcysteine	The N-acetyl derivative of CYSTEINE. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates.	Mercapturic Acid,Acemuc,Acetabs,Acetylcystein AL,Acetylcystein Atid,Acetylcystein Heumann,Acetylcystein Trom,Acetylcysteine Hydrochloride,Acetylcysteine Sodium,Acetylcysteine Zinc,Acetylcysteine, (D)-Isomer,Acetylcysteine, (DL)-Isomer,Acetylcysteine, Monoammonium Salt,Acetylcysteine, Monosodium Salt,Acetylin,Acetyst,Acétylcystéine GNR,Airbron,Alveolex,Azubronchin,Bisolvon NAC,Bromuc,Broncho-Fips,Broncholysin,Broncoclar,Codotussyl,Cystamucil,Dampo Mucopect,Eurespiran,Exomuc,Fabrol,Fluimucil,Fluprowit,Frekatuss,Genac,Hoestil,Ilube,Jenacystein,Jenapharm,Lantamed,Larylin NAC,Lindocetyl,M-Pectil,Muciteran,Muco Sanigen,Mucomyst,Mucosil,Mucosol,Mucosolvin,N-Acetyl-L-cysteine,N-Acetylcysteine,NAC AL,NAC Zambon,Optipect Hustengetränk,Siccoral,Siran,Solmucol,acebraus,durabronchal,mentopin Acetylcystein,Acetylcystein, mentopin,Acid, Mercapturic,Broncho Fips,BronchoFips,Hustengetränk, Optipect,Hydrochloride, Acetylcysteine,M Pectil,MPectil,Monoammonium Salt Acetylcysteine,Monosodium Salt Acetylcysteine,Mucopect, Dampo,N Acetyl L cysteine,N Acetylcysteine,NAC, Bisolvon,Sanigen, Muco,Sodium, Acetylcysteine,Zambon, NAC,Zinc, Acetylcysteine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D013438	Sulfhydryl Compounds	Compounds containing the -SH radical.	Mercaptan,Mercapto Compounds,Sulfhydryl Compound,Thiol,Thiols,Mercaptans,Compound, Sulfhydryl,Compounds, Mercapto,Compounds, Sulfhydryl