Adenosine Triphosphate

Nucleoside diphosphate kinase (Ndk) is ubiquitous and highly conserved multifunctional key enzyme in nucleotide metabolism. It generates nucleoside triphosphates (NTPs) by transfer of gamma-phosphates from nucleoside triphosphates such as ATP or GTP to nucleoside diphosphate. The formation of an autophosphorylated enzyme intermediate is involved in that mechanism. The phosphate is usually supplied by ATP and Ndk activity in different subcellular compartments. Ndk may regulate the crucial balance between ATP and GTP or other nucleoside triphosphates. Ndk is playing an important role in bacterial pathogenesis and emerging evidences recognize multiple roles of Ndk in host-microbe interaction. Here, I review some examples of the role of Ndk in intra- and extracellular microorganism.
Adenosine Triphosphate ; Guanosine Triphosphate ; Nucleoside-Diphosphate Kinase

The effect of indomethacin on Na-K-ATPase and K-pNPPase activity was studied with rat brain homogenate. The results were as follows : 1) Indomethacin inhibited both Na-K-ATPase and K-pNPPase in a dose-related pattern. 2) Inhibition mode of indomethacin for K+ in both Na-K-ATPase and K-pNPPase was competitive type. 3) Indomethacin showed stimulative effect at lower sodium concentration below 10mM, and showed inhibitory effect at higher sodium concentration on Na-K-ATPase and K-pNPPase activity, and the inhibitory effect was slightly increased with increasing concentration of sodium. 4) The inhibitory effect of indomethacin on Na-K-ATPase activity was increased with increasing ATP concentration, but was not affected by Mg++ concentration. These results indicate that indomethacin inhibits Na-K-ATPase activity by inhibiting K+- dependent dephosphorylation steps.
Adenosine Triphosphate ; Animals ; Brain* ; Indomethacin* ; Rats* ; Sodium

Effect of Mercury chloride on the synthesis of NO2- and ATP were observed in EMT-6 cells which were culture with cytokines(IL-1alpha and IFN-gamma) and various concentrations of mercury chloride from 0.05 to 0.08 M. Viability of EMT-6 cells were observed above 90% in almost groups. There were not significant differences in the viability between mercury supplemented groups and control group. It suggests viability of EMT-6 cells were not influenced by these concentrations of mercury chloride. Results of the synthesis of nitrite showed significant time and group effect. There is a significant interaction effect between concentration of mercury chloride and culture time. The effect of various concentration of mercury chloride is not the same for all levels of culture time. There were significant differences in the synthesis of nitrite between mercury chloride supplemented groups and control group, and the synthesis of nitrite in EMT-6 cell by the supplement of mercury chloride was significantly decreased in a dose-dependent manner. Results of the synthesis of ATP showed a significant group effect, and the time main effect and the Group x Time interaction were also significant. There were significant differences in the synthesis of ATP between mercury chloride supplemented groups and control group, and the synthesis of ATP in EMT-6 cell by the supplement of mercury chloride was significantly decreased in a dose-dependent manner. These results suggest that the disorder of cell mediated immunity by mercury chloride could be related to the inhibition of nitric oxide synthesis which will be caused by the decreased synthesis of ATP.
Adenosine Triphosphate* ; Immunity, Cellular ; Nitric Oxide

OBJECTIVETo study the mechanism in masticatory muscle dysfunctional induced by hemimastication.

METHODSCa2+ contents were measured with atomic absorption spectrometry; calcinuerin were measured with colorimetric method; muscle fiber types were measured with adenosine-triphosphate (ATPase) staining.

RESULTS(1) Compared with the controls, Ca2+ contents in experimental group had the higher level except 8 weeks (P < 0.05). (2) The ratio of slow fiber in experimental group increased, higher than the match groups (P < 0.05). (3) With Ca2 contents rise, the activities of calcinuerin present a bell-like shape. (4) The ratio of slow-type fiber was positively correlated to the activities of calcinuerin (r = 0.876, P < 0.05).

CONCLUSIONThe signal way of muscle fiber growth and fiber transformation were activated by high concentration of calcium, then, muscle fiber transferred from fast to slow type. It may play an important role in the mechanism that hemimastication result in masticatory muscles dysfunction.

BACKGROUND AND OBJECTIVES: There are conflicting results about ciliary activity in chronic rhinosinusitis (CRS). And dynamic movements reacting to various stimuli in sinusitis mucosa have been studied rarely. This study was designed to investigate the ciliary activity according to the severity of sinusitis and clinical symptoms. We aimed to identify the dynamic ciliary activity in response to purinergic stimulation in sinusitis. SUBJECTS AND METHOD: Nasal mucosal samples were obtained from 44 CRS and 20 normal subjects. We measured ciliary beat frequency (CBF) in the basal and activated status. For evaluating the correlation of CBF with clinical findings, nasal symptoms, endoscopic findings, CT findings, allergy tests, and olfactory tests were reviewed. RESULTS: No significant differences were found in basal CBF between normal and CRS mucosa. However, the CBF stimulated by ATP in normal and CRS mucosa showed marked differences: both the maximal increase and duration of increased CBF by ATP were significantly reduced in CRS mucosa. The olfactory test showed significant correlation with basal CBF, but the presence of allergy or nasal symptoms did not show significant correlation with the basal CBF. The CT score and presence of nasal polyposis showed negative correlation with the basal CBF (p<0.05). CONCLUSION: The basal CBF of normal and CRS mucosa showed no difference. However, dynamic ciliary activity responding to purinergic stimulation was markedly attenuated in sinusitis mucosa. The severity of sinusitis and presence of polyposis negatively affected CBF.
Adenosine Triphosphate ; Hypersensitivity ; Mucous Membrane ; Sinusitis

ATP is an important cofactor involved in many biocatalytic reactions that require energy input. Polyphosphate kinases (PPK) can provide energy for ATP-consuming reactions due to their cheap and readily available substrate polyphosphate. We selected ChPPK from Cytophaga hutchinsonii for substrate profiling and tolerance analysis. By molecular docking and site-directed mutagenesis, we rationally engineered the dual-substrate channel cavity of polyphosphate kinase to improve the catalytic activity of PPK. Compared with the wild type, the relative enzyme activity of the screened mutant ChPPK_K81H-K103V increased by 326.7%. Meanwhile, the double mutation expanded the substrate utilization range and tolerance of ChPPK, and improved its heat and alkali resistance. Subsequently, we coupled the glutathione bifunctional enzyme GshAB and ChPPK_K81H-K103V based on this ATP regeneration system, and glutathione was produced by cell-free catalysis upon disruption of cells. This system produced (25.4±1.9) mmol/L glutathione in 6 h upon addition of 5 mmol/L ATP. Compared with the system before mutation, glutathione production was increased by 41.9%. After optimizing the buffer, bacterial mass and feeding time of this system, (45.2±1.8) mmol/L glutathione was produced in 6 h and the conversion rate of the substrate l-cysteine was 90.4%. Increasing the ability of ChPPK enzyme to produce ATP can effectively enhance the conversion rate of substrate and reduce the catalytic cost, achieving high yield, high conversion rate and high economic value for glutathione production by cell-free catalysis. This study provides a green and efficient ATP regeneration system that may further power the ATP-consuming biocatalytic reaction platform.
Molecular Docking Simulation ; Catalysis ; Glutathione ; Adenosine Triphosphate

No abstract available.
Adenosine Triphosphate* ; Adenosine* ; Child* ; Humans ; Infant* ; Tachycardia, Supraventricular*

Adenosine triphosphate (ATP) regeneration systems are essential for efficient biocatalytic phosphoryl transfer reactions. Polyphosphate kinase (PPK) is a versatile enzyme that can transfer phosphate groups among adenosine monophosphate (AMP), adenosine diphosphate (ADP), ATP, and polyphosphate (Poly P). Utilization of PPK is an attractive solution to address the problem of ATP regeneration due to its ability to use a variety of inexpensive and stable Poly P salts as phosphate group donors. This review comprehensively summarizes the structural characteristics and catalytic mechanisms of different types of PPKs, as well as the variations in enzyme activity, catalytic efficiency, stability, and coenzyme preference observed in PPKs from different sources. Moreover, recent advances in PPK-mediated ATP regeneration systems and protein engineering of wild-type PPK are summarized.
Adenosine Triphosphate/metabolism* ; Adenosine Monophosphate ; Polyphosphates/metabolism* ; Catalysis ; Regeneration

We cultured the rabbit inner medullary collecting duct (IMCD) cells as monolayers on collagen-coated membrane filters, and investigated distribution of the P2Y receptors by analyzing nucleotide-induced short circuit current (Isc) responses. Exposure to different nucleotides of either the apical or basolateral surface of cell monolayers stimulated Isc. Dose-response relationship and cross-desensitization studies suggested that at least 3 distinct P2Y receptors are expressed asymmetrically on the apical and basolateral membranes. A P2Y2-like receptor, which responds to UTP and ATP, is expressed on both the apical and basolateral membranes. In addition, a uracil nucleotide receptor, which responds to UDP and UTP, but not ATP, is expressed predominantly on the apical membrane. In contrast, a P2Y1-like receptor, which responds to ADP and 2-methylthio-ATP, is expressed predominantly on the basolateral membrane. These nucleotides stimulated intracellular cAMP production with an asymmetrical profile, which was comparable to that in the stimulation of Isc. Our results suggest that the adenine and uracil nucleotides can interact with different P2Y nucleotide receptors that are expressed asymmetrically on the apical and basolateral membranes of the rabbit IMCD cells, and that both cAMP- and Ca2+-dependent signaling mechanisms underlie the stimulation of Isc.
Adenine ; Adenosine Diphosphate ; Adenosine Triphosphate ; Membranes ; Nucleotides ; Uracil ; Uracil Nucleotides ; Uridine Diphosphate ; Uridine Triphosphate