Possible regulation mechanism of potent nucleoside triphosphate hydrolase in Toxoplasma gondii. 1987

T Asai, and T Kim
Dept. of Microbiology, Tokyo Medical College, Japan.

A dormant enzyme, nucleoside triphosphate hydrolase (EC 3.6.1.3) purified from the tachyzoite of Toxoplasma gondii, was activated by the treatment with dithiothreitol. The catalytic activity remained after exclusion of dithiothreitol from the enzyme solution with a Sephadex G-25 column. This activity was completely blocked by the additional treatment with N-ethylmaleimide. It was concluded that the activation occurred through the reductive cleavage of disulfide bond on the enzyme. The reduced type of thioredoxin, partially purified from mouse liver, could replace the effect of dithiothreitol. These results strongly suggest that the enzyme activity is regulated by the oxido-reduction change in the enzyme molecule.

UI MeSH Term Description Entries
D010744 Phosphoric Monoester Hydrolases A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate. Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D004229 Dithiothreitol A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols. Cleland Reagent,Cleland's Reagent,Sputolysin,Clelands Reagent,Reagent, Cleland,Reagent, Cleland's
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
D005033 Ethylmaleimide A sulfhydryl reagent that is widely used in experimental biochemical studies. N-Ethylmaleimide,N Ethylmaleimide
D000255 Adenosine Triphosphate An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter. ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
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
D001426 Bacterial Proteins Proteins found in any species of bacterium. Bacterial Gene Products,Bacterial Gene Proteins,Gene Products, Bacterial,Bacterial Gene Product,Bacterial Gene Protein,Bacterial Protein,Gene Product, Bacterial,Gene Protein, Bacterial,Gene Proteins, Bacterial,Protein, Bacterial,Proteins, Bacterial
D013879 Thioredoxins Hydrogen-donating proteins that participates in a variety of biochemical reactions including ribonucleotide reduction and reduction of PEROXIREDOXINS. Thioredoxin is oxidized from a dithiol to a disulfide when acting as a reducing cofactor. The disulfide form is then reduced by NADPH in a reaction catalyzed by THIOREDOXIN REDUCTASE. Thioredoxin,Thioredoxin 1,Thioredoxin 2,Thioredoxin-1,Thioredoxin-2
D014122 Toxoplasma A genus of protozoa parasitic to birds and mammals. T. gondii is one of the most common infectious pathogenic animal parasites of man. Toxoplasma gondii,Toxoplasma gondius,Toxoplasmas,gondius, Toxoplasma
D043583 Nucleoside-Triphosphatase An enzyme which catalyzes the hydrolysis of nucleoside triphosphates to nucleoside diphosphates. It may also catalyze the hydrolysis of nucleotide triphosphates, diphosphates, thiamine diphosphates and FAD. The nucleoside triphosphate phosphohydrolases I and II are subtypes of the enzyme which are found mostly in viruses. NTPase,Nucleoside Triphosphatase,Nucleoside Triphosphate Phosphohydrolase,Nucleoside Triphosphate Phosphohydrolase I,Nucleoside Triphosphate Phosphohydrolase II,Nucleosidetriphosphatase,Phosphohydrolase, Nucleoside Triphosphate,Triphosphatase, Nucleoside,Triphosphate Phosphohydrolase, Nucleoside

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