• Biomolecules & Therapeutics
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• v.3 no.3
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• pp.205-209
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• 1995

The novel compound KH 3218 was synthesized and evaluated for its ability to inhibit the gastric H$^{＋}$＋ $K^{＋}$ ATPase activity in vitro as well as to lessen gastric acid secretion in vivo. KH 3218 inhibited rabbit gastric H$^{＋}$＋ $K^{＋}$ ATPase in a concentration and time dependent manner. $IC_{50}$/ value was estimated to be about 15 $\mu$M. The inhibition of the H$^{＋}$＋ $K^{＋}$ ATPase by KH 3218 was blocked by sulfhydryl reducing agents, dithiothreitol or $\beta$-mercaptoethanol. The inhibition of the enzyme was not reversible by 50 fold dilution of the incubation mixtures, suggesting the irreversible nature of the inactivation. In the pylorus-ligated rift, KH 3218 reduced the total acid output as compared with the control. In addition, KH 3218 was capable of inhibiting H. pylori urease activity. These data suggest that KH 3218 is a potent inhibitor for H$^{＋}$＋ $K^{＋}$ ATPase activity as well as for gastric acid secretion, and has a potential to be developed as a novel antiulcer agent.

• Applied Biological Chemistry
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• v.39 no.3
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• pp.189-194
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• 1996

The effects of scorpion (Leiurus quinquestriatus hebraeus, Lqh) venom were evaluated on the activities of microsomal $Ca^{2+}-ATPase$ and $Ca^{2+}$ release channel prepared from the epithelial cells of pig airway. Whole venom of Lqh $(120\;{\mu}g/ml)$ increased the activity of microsomal $Ca^{2+}-ATPase$ about 32% in the tight-sealed microsomes and about 28% in the Triton X-100-treated or $Ca^{2+}$ ionophore A23187-treated leaky microsomes. Thapsigargin, a specific antagonist of $Ca^{2+}-ATPase$, inhibited 42% of total ATPase activity and also completely blocked the effects of Lqh venom, suggesting that Lqh venom directly activiates the microsomal $Ca^{2+}-ATPase$. In order to determine if Lqh venom increases the microsomal uptake of $^{45}Ca^{2+}$, Lqh venom was added in the uptake medium. The Lqh venom increased microsomal $^{45}Ca^{2+}$ uptake up to ${\sim}20%$ and the increase was only observed when heparin, an antagonist of $InsP_3$ receptor channel, was added in the uptake medium. Lqh venom in the absence of heparin unexpectedly decreased the rate and the amount of $^{45}Ca^{2+}$ uptake. These results were explained by simultaneous increases in $^{45}Ca^{2+}$ release as well as $^{45}Ca^{2+}$ uptake by Lqh venom. Lqh venom itself increased the release of $^{45}Ca^{2+}$ as much as $^{45}Ca^{2+}$ release by $4\;{\mu}m\;InsP_3$, implying that Lqh venom also activates $InsP_3$ receptor, microsomal $Ca^{2+}$ release channel. Based on these results, we suggest that the Lqh venom consists of at least two components; one activates the $InsP_3$ receptor and the other avates the $Ca^{2+}-ATPase$. Currently we a investigating the chemical and electrophysiological properties of the active components of Lqh venom.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.298-303
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• 1999

In order to characterize the effects of heavy metal ions on the microsomal ATPase activities, microsomes were prepared from the roots of tomato plant and the activity of microsomal ATPase was measured by an enzyme-coupled assay. $Hg^{2+}$ inhibited the activity of microsomal ATPase in a dose-dependent manner, while $Gd^{3+}$, $Fe^{3+}$, $La^{3+}$, $Zn^{2+}$, and $Pb^{2+}$ inhibited not only the ATPase activity but also the activities of enzymes used in the assay. However, $Cs^+$ and $Ba^{2+}$ showed no significant effect. $Hg^{2+}$ inhibited the activities of both plasma membrane and vacuolar membrane $H^+-ATPases$. In the dose-response to $Hg^{2+}$, the activities of both microsomal $H^+-ATPases$ were severely inhibited at the concentration of $Hg^{2+}$ above $10\;{\mu}M$ and were completely inhibited at 1 mM $Hg^{2+}$. Apparent Ki values of $Hg^{2+}$ on the inhibitions of plasma membrane and vacuolar membrane $H^+-ATPases$ were $80\;{\mu}M$ and $58\;{\mu}M$, respectively. The $Hg^{2+}$-induced inhibitions were reversible since the addition of dithiothreitol completely reversed the inhibitory effects of $Hg^{2+}$. These results suggest that the inhibitory effects of $Hg^{2+}$ on both plasma, membrane and vacuolar membrane $H^+-ATPases$ are nonselective and reversible.

• Biomolecules & Therapeutics
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• v.14 no.3
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• pp.143-147
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• 2006

In the mouse leukemic monocyte cell line RAW 264.7, the vacuolar-type $(H^+)$-ATPase (V-ATPase) inhibitor bafilomycin $A_1$ at 10 and 100 nM decreased cell growth and survival as determined by 3-(4,5-dimethyl(thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in a concentration-dependent manner. At such concentrations, bafilomycin $A_1$ induced nitric oxide (NO) production through the expression of inducible nitric oxide synthase (iNOS). The bafilomycin $A_1$-induced NO production was inhibited by the NOS inhibitor $N^G$-monomethyl-L-arginine acetate (L-NMMA). Our findings suggest that the V-ATPase inhibitor bafilomycin $A_1$ induces NO production through the expression of iNOS protein.

• Journal of Environmental Science International
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• v.9 no.3
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• pp.209-214
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• 2000

The preventive effects of sodium molybdate on the acute toxicity of lead were studied by investigating tissue accumulation of lead, changes of nerve conduction velocity and concentrations of metabolites related to function of sciatic nerve in rats treated with lead, sodium molybdate and both, respectively. In lead-intoxicated rat, the conduction velocity, myo-inositol concentration and $Na^{+}/K^{+}$ ATPase activity of sciatic nerve were decreased by about 33 %, 48 % and 58 %, respectively. However, sodium molybdate treatment significantly normalized the conduction velocity, $Na^{+}/K^{+}$ ATPase activity and myo-inositol concentration of sciatic nerve in lead-intoxicated rat. Also, sodium molybdate treatment decreased the contents of lead in blood and sciatic nerve through promotion of urinary excretion of lead. But sodium molybdate treatment did not affect the glucose concentration in sciatic nerve. These results suggest that sodium molybdate prevented peripheral neuropathy not only by reducing lead contents in sciatic nerve and blood, but also by enhancing $Na^{+}/K^{+}$ ATPase activity in sciatic nerve.

• Journal of Life Science
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• v.6 no.1
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• pp.1-5
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• 1996

Using differential hybridization, a cDNA clone was isolated fortuitously from Amaranthus viridis and sequenced. This nucleotide sequence exhibited 55.1% identity with vma6 which encodes the 36-kD subunit of the vacuolar proton transporting ATPase in Saccharmoyces cerevisiae. The predicted open reading frame encodes a protein of 221 amino acid sequence with a calculated molecular weight of 25,452 and reveals high levels of similarity with subunit D polypeptide of vacuolar H -ATP(e.g., 48.5, 52.1 and 49.3% identity to the vacuolar 36-kD chain of yeast, vacuolar 32-kD polypeptide IV of human and vacuolar 28-kD protein of bovine chromaffin granules, respectively). The hydropathy index computation revealed that this predicted protein is a peripheral protein. These results indicated that the predicted protein may play a sturctural role in the vaculor H -ATPase as does gamma subunit in V-type ATPase.

• Journal of Preventive Medicine and Public Health
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• v.23 no.4 s.32
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• pp.371-390
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• 1990

Production of free radicals of superoxide anion in tissues by cadmium, activities of superoxide dismutase and catalase to protect tissue damages caused by the free radicals and ATPase that plays an important role in energy metabolism at cellular level were investigated. Experiments in vivo were conducted with liver, kidney and testicle tissue homogenates of rats adding $0.05{\sim}0.50mM$ cadmium chloride, and in vivo experiments administering single dose of 5 mg of cadmium/kg of body weight in 0.1% cadmium chloride solution intraperitoneally 48 hours prior to evisceration. Production of superoxide radicals in liver and testicle increased with addition of cadmium in vitro, but not in kidney. In vivo experiments, however, superoxide radicals slightly increased in liver and kidney but not in testicle. Superoxide dismutase (Cu, Zn-SOD and Mn-SOD), catalase and ATPase (total, $Mg^{++}-\;&\;Na^+,\;K^+-$) activity decreased in the presence of cadimium in dose dependent manner. Reduction of these enzyme activities varied not only with dosage of cadmium but also with type of tissue and between in vitro and in vivo experiment.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.4
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• pp.275-281
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• 2013

Astrocytes are reported to have critical functions in ischemic brain injury including protective effects against ischemia-induced neuronal dysfunction. Na-K ATPase maintains ionic gradients in astrocytes and is suggested as an indicator of ischemic injury in glial cells. Here, we examined the role of the Na-K ATPase in the pathologic process of ischemic injury of primary cultured astrocytes. Chemical ischemia was induced by sodium azide and glucose deprivation. Lactate dehydrogenase assays showed that the cytotoxic effect of chemical ischemia on astrocytes began to appear at 2 h of ischemia. The expression of Na-K ATPase ${\alpha}1$ subunit protein was increased at 2 h of chemical ischemia and was decreased at 6 h of ischemia, whereas the expression of ${\alpha}1$ subunit mRNA was not changed by chemical ischemia. Na-K ATPase activity was time-dependently decreased at 1, 3, and 6 h of chemical ischemia, whereas the enzyme activity was temporarily recovered to the control value at 2 h of chemical ischemia. Cytotoxicity at 2 h of chemical ischemia was significantly blocked by reoxygenation for 24 h following ischemia. Reoxygenation following chemical ischemia for 1 h significantly increased the activity of the Na-K ATPase, while reoxygenation following ischemia for 2 h slightly decreased the enzyme activity. These results suggest that the critical time for ischemia-induced cytotoxicity of astrocytes might be 2 h after the initiation of ischemic insult and that the increase in the expression and activity of the Na-K ATPase might play a protective role during ischemic injury of astrocytes.

• 대한약리학회:학술대회논문집
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• 2006.10a
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• pp.118.2-118.2
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• 2006

• The Korean Journal of Zoology
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• v.23 no.2
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• pp.61-68
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• 1980

Quantitative analysis of the activities of transport ATPases as well as alkaline phosphatase of the mouse uterus was carried out during the estrous cycle. Even though the proportional patterns of the enzyme activities were similar each another between the stages of estrous cycle, the absolute activities of the enzymes except $K^+$-dependent and $Na^+$, $K^+$-activated ATPases at the time of estrus were significantly (p<0.025) higher than that at any other time of the estrous cycle. That is, the activities of $K^+$-dependent and $Na^+$, $K^+$-activated ATPases were negligible during the period of time from diestrus to estrus while the little activities (0.04 $\\sim$ 0.05$\\mu$M/mg protein/hr in average, $6\\sim7$% of the total enzyme activity) of these enzymes appeared at the time of metaestrus. On the other hand, at the time of estrus, the activities of $Mg^++$-dependent phosphatase, transport ATPase and alkaline phosphatase were rapidly and tremendously increased to be 0.69 (35%), 0.42 (21%) and 1.58 (79%), respectively. The activity of alkaline phosphatase was in the range of 0.60 $\\sim$ 1.58 (79 $\\sim$ 90%) and predominant throughout the estrous cycle. The activity of $Mg^++$-dependent alkaline phosphatase was estimated as 12 $\\sim$ 16% of the total enzyme activity. Therefore, it is assumed likely that $K^+$-dependent and $Na^+$, $K^+$-activated ATPases are not the main factors to control the fluid accumulation at the time of estrus, but may be the factors to reabsorb the luminal fluid into the uterine epithelium at the time of metaestrus, and that $Mg^++$-dependent phosphatase, transport ATPase and alkaline phosphatase must be closely involved in the secretion of luminal fluid from the epithelial cells of the mouse uterus.