Nitric oxide synthase in cat brain: cofactors--enzyme-substrate interaction. 1996

J F Côté, and A G Roberge
INRS-Santé, Université du Québec, Pointe-Claire, Canada.

Nitric oxide, derived from L-arginine by the enzyme nitric oxide synthase, is an activator of the soluble guanylate cyclase and a cellular messenger. This work demonstrates that, in cat brain, the neuronal constitutive nitric oxide synthase activity is a) NADPH/calcium dependent, b) independent upon exogenous calmodulin in crude brain supernatant, c) significantly enhanced by exogenous FAD and tetrahydrobiopterin (Vmax: 118 instead of 59.4 pmol of citrulline formed .mg of prot.-1 min-1, d) inhibited by calcium chelators and calmodulin antagonist, and e) present in several neuroanatomical structures. Moreover, the Km value for L-arginine was of 11 microM instead of 41 microM in the presence of FAD and tetrahydrobiopterin in the incubation mixture, thus demonstrating that these cofactors are able to stabilize the enzyme-substrate interactions.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008297 Male Males
D009249 NADP Nicotinamide adenine dinucleotide phosphate. A coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled by pyrophosphate linkage to the 5'-phosphate adenosine 2',5'-bisphosphate. It serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). (Dorland, 27th ed) Coenzyme II,Nicotinamide-Adenine Dinucleotide Phosphate,Triphosphopyridine Nucleotide,NADPH,Dinucleotide Phosphate, Nicotinamide-Adenine,Nicotinamide Adenine Dinucleotide Phosphate,Nucleotide, Triphosphopyridine,Phosphate, Nicotinamide-Adenine Dinucleotide
D009928 Organ Specificity Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen. Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D001921 Brain The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM. Encephalon
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002415 Cats The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801) Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat
D004492 Edetic Acid A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive. EDTA,Edathamil,Edetates,Ethylenediaminetetraacetic Acid,Tetracemate,Calcium Disodium Edetate,Calcium Disodium Versenate,Calcium Tetacine,Chelaton 3,Chromium EDTA,Copper EDTA,Coprin,Dicobalt EDTA,Disodium Calcitetracemate,Disodium EDTA,Disodium Ethylene Dinitrilotetraacetate,Distannous EDTA,Edetate Disodium Calcium,Edetic Acid, Calcium Salt,Edetic Acid, Calcium, Sodium Salt,Edetic Acid, Chromium Salt,Edetic Acid, Dipotassium Salt,Edetic Acid, Disodium Salt,Edetic Acid, Disodium Salt, Dihydrate,Edetic Acid, Disodium, Magnesium Salt,Edetic Acid, Disodium, Monopotassium Salt,Edetic Acid, Magnesium Salt,Edetic Acid, Monopotassium Salt,Edetic Acid, Monosodium Salt,Edetic Acid, Potassium Salt,Edetic Acid, Sodium Salt,Ethylene Dinitrilotetraacetate,Ethylenedinitrilotetraacetic Acid,Gallium EDTA,Magnesium Disodium EDTA,N,N'-1,2-Ethanediylbis(N-(carboxymethyl)glycine),Potassium EDTA,Stannous EDTA,Versenate,Versene,Acid, Edetic,Acid, Ethylenediaminetetraacetic,Acid, Ethylenedinitrilotetraacetic,Calcitetracemate, Disodium,Dinitrilotetraacetate, Disodium Ethylene,Dinitrilotetraacetate, Ethylene,Disodium Versenate, Calcium,EDTA, Chromium,EDTA, Copper,EDTA, Dicobalt,EDTA, Disodium,EDTA, Distannous,EDTA, Gallium,EDTA, Magnesium Disodium,EDTA, Potassium,EDTA, Stannous,Edetate, Calcium Disodium,Ethylene Dinitrilotetraacetate, Disodium,Tetacine, Calcium,Versenate, Calcium Disodium
D004533 Egtazic Acid A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID. EGTA,Ethylene Glycol Tetraacetic Acid,EGATA,Egtazic Acid Disodium Salt,Egtazic Acid Potassium Salt,Egtazic Acid Sodium Salt,Ethylene Glycol Bis(2-aminoethyl ether)tetraacetic Acid,Ethylenebis(oxyethylenenitrile)tetraacetic Acid,GEDTA,Glycoletherdiamine-N,N,N',N'-tetraacetic Acid,Magnesium-EGTA,Tetrasodium EGTA,Acid, Egtazic,EGTA, Tetrasodium,Magnesium EGTA
D005260 Female Females

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