Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.25 (triphosphatase)
 1,529 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RNA-dependent DNA polymerase activity of avian myeloblastosis virions as measured by the incorporation of [3H]TTP into trichloroacetic acid-precipitable material was very low. This apparent low polymerase activity was observed with virions isolated either from leukemic chicken plasma or from the supernatant of cultured leukemic myeloblasts. The inhibition of reverse transcriptase activity was caused by nucleoside triphosphatase present in avian myeloblastosis virions and could be reversed by ADP.
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PMID:Inhibition of virion-associated reverse transcription by nucleoside triphosphatase in avian myeloblastosis virus. 615 6

The nucleoside triphosphatase (EC 3.6.1.15) was isolated from rat liver cytosol and purified 600-fold. The enzyme hydrolyzes all NTPs and dNTPs, splits NDPs and dNDPs at a low rate and does not destroy NMPs and dNMPs. The phosphatase consists of a single subunit with molecular weight of 65 000. The chromatin fraction of the enzyme is fully bound to the membrane, whereas the cytosol fraction contains 15-30% of the membrane-bound enzyme. Both free and membrane-bound phosphatases possess identical functional properties. The enzymatic activity has a pH-optimum of 4.0--4.5, is increased in the presence of Me2+ and is unaffected by ouabain, Triton X-100, N-ethylmaleimide, NaF or DNA, but is inhibited by NaCl, Pi and PPi. The value of Km is equal to 20 microM for TTP splitting. Since the NTP pool is essentially changed throughout the cell cycle, it is suggested that the nucleoside triphosphatase can participate in the nucleotide pool regulation.
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PMID:[Non-specific acid nucleoside triphosphatase from cytosol and chromatin of rat liver: partial purification and general properties]. 628 41

1. Parotid plasma membrane nonpump low-affinity Ca(2+)-ATPase, which possesses high-affinity (Ca2+ + Mg2+)-ATPase activity, was characterized. 2. Purified Ca(2+)-ATPase hydrolyzed the nucleoside triphosphates, GTP, ITP, CTP, UTP, TTP (67-93% of ATP) and nucleoside diphosphates, ADP, GDP, IDP, CDP, TDP (12-40% of ATP) but not AMP and p-NPP. 3. The maximum activities of Ca(2+)- and (Ca2+ + Mg2+)-ATPases were obtained in the presence of 1 mM and 0.13 microM Ca2+, respectively. 4. The Km values for Ca2+ in Ca(2+)- and (Ca2+ + Mg2+)-ATPases were 0.2 mM and 22 nM, respectively. 5. The activities of both Ca(2+)- and (Ca2+ + Mg2+)-ATPases were found in the right-side-out-vesicles obtained from the plasma membrane-rich fraction. 6. These features suggest that Ca(2+)-ATPase is an ecto-Ca(2+)-dependent nucleoside triphosphatase.
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PMID:The possibility that Ca(2+)-ATPase from the plasma membrane-rich fraction of bovine parotid gland is ecto-Ca(2+)-dependent nucleoside triphosphatase. 806 15