• Journal of the korean academy of Pediatric Dentistry
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• v.10 no.1
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• pp.139-147
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• 1983

This study was undertaken to evaluate the physiological roles & mechanism of $Ca^{++}$-ATPase & $Mg^{++}$-ATPase in human dental pulp. Each specimen of dental pulp was obtained from the freshly extracted, freeze-dried 242 teeth. $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were measured by the release of inorganic phosphate & protein with Spectrophotometer. The results were as follows; 1. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significantly increased in developing teeth. 2. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significantly decreased in nonvital teeth. 3. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity were significant decreased in deciduous teeth. 4. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase activity didn't have relation with dental caries. 5. The $Ca^{++}$-ATPase & $Mg^{++}$-ATPase were activated by either $Ca^{++}$ alone or $Mg^{++}$ alone.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.157-164
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• 1986

Since it has been reported that vanadate inhibits $Ca^{++}-ATPase$ activity without affecting $Ca^{++}$ uptake, this study was undertaken to investigate the effects of vanadate on $Ca^{++}-ATPase$ activity and $Ca^{++}$ uptake in the sarcoplasmic reticulum of rat skeletal muscle. The following results were obtained. 1) $Ca^{++}$ activated ATPase activity of the intact sarcoplasmic reticulum was significantly inhibited when vanadate was added to the incubation medium at concentration greater than $10^{-6}\;M$. However $Mg^{++}$-ATPase activity of the intact SR was not affected by vanadate at concentrations ranging from $10^{-7}\;to\;10^{-4}\;M.$ Similarly, $Ca^{++}-ATPase$ activity in sonicated sarcoplasmic reticulum was significantly reduced by vanadate at a concentration $10^{-7}$ M or higher. 2) The uptake of $Ca^{++}$ by isolated sarcoplasmic reticulum was also inhibited by vanadate under the conditions where the turnover rate of $Ca^{++}-ATPase$ was made to increase. These results suggest that the inhibition of $Ca^{++}$ uptake by vanadate may be correlated with that of $Ca^{++}-ATPase$ if experimental conditions are properly set.

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.198-207
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• 1997

To explore the action mechanism of Ijintang in the brain, the authors investigated the effects of Ijintang fractions on MgNaK ATPase and MgCa ATPase in rat brain synaptosomes prepared from cerebral cortex. The activities of MgNaK ATPase and MgCa ATPase were assayed by the level of inorganic phosphate liberated from the hydrolysis of ATP. Fraction WH-95-7 at the concentration of $10^{-2}%$ decreased the activity of MgNaK ATPase about 34.1% and also reduced the activity of MgCa ATPase about 49.3% But, other fractions (WB-95-7, WC-95-7, MB-95-7, MC-95-7, MH-95-7) did not significantly changed the activities of the MgNaK ATPase and MgCa ATPase The decreased activity of MgNaK ATPase by WH-95-7 will decrease the rate of $Ca^{2+}$ efflux, probably via an Na-Ca exchange mechanism and will increase the rate of $Ca^{2+}$ entry by the depolarization of nerve terminals. The reduced activity of MgCa ATPase by WH-95-7 will result in the decreased efflux of $Ca^{2+}$. As a conclusion, it can be speculated that lithium elevates the intrasynaptosomal $Ca^{2+}$ concentration via inhibition of the activities of MgNaK ATPase and MgCa ATPase. and this increased $[Ca^{2+}]i$ will cause the release of neurotransmitters.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.269-277
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• 1995

Membrane vesicles were prepared by differential centrifugation from epithelial cells of porcine trachea. Total activity of microsomal ATPases was measured spectrophotometrically by a coupled enzyme assay. The steady-state activity of the enzyme was $329{\pm}10$ nmol/min mg protein. Thapsigargin, a specific antagonist of intracellular $Ca^{2+}-ATPase$, inhibited about 50% of the activity, leaving $178{\pm}18\;nmol/min .mg$ protein (n=6), indicating that the $Ca^{2+}-ATPase$ is one of the major microsomal ATPases. The microsomes used in this study appeared to be tight-sealed vesicles since they showed saturation in $^{45}Ca^{2+}$ uptake experiments. Inositol 1,4,5-trisphosphate $InsP_{3}, 4\;{\mu}M$, an agonist of $InsP_{3}$-sensitive $Ca^{2+}$ release channel ($InsP_{3}$, receptor), and Ca-ionophore A23187 $(10\;{\mu}M)$ induced $^{45}Ca^{2+}$ releases of 20% and 50% of stored $^{45}Ca^{2+}$, respectively. The addition of $(10\;{\mu}M\;InsP_{3}$ also increased the microsomal ATPase activity from $282{\pm}8$ nmol/min mg protein to $334{\pm}21$ nmol/min . mg protein in the intact vesicles. Similar increase in the activity was observed by making microsomes leaky (uncoupling) using the Ca-ionophore A23187. ;$InsP_{3}-induced$ effects were blocked by either thapsigargin or heparin suggesting that: 1) the $InsP_{3}-induced$ increase in ATPase activity is mediated by microsomal $Ca^{2+}-ATPase$, and 2) dissipation of $Ca^{2+}$ gradient across the microsomal membrane is responsible for the $InsP_{3}-induced$ effect. In order to test the dependence of the $Ca^{2+}-ATPase$ activity on the activity of $InsP_{3}-induced$ the activity of ATPases was monitored in various concentrations of free $Ca^{2+}$ using $EGTA-Ca^{2+}$ buffers. The $Ca^{2+}$-dependent biphasic change is the well-known character of $InsP_{3} receptor but not of microsomal $Ca^{2+}-ATPase$ in non-excitable cells; however, the activity of microsomal ATPase appeared biphasic and a maxim진 activity of $397{\pm}36nmol/min\;.mg$ protein was obtained in the solution containing 100 nM free $Ca^{2+}$. Below or above this concentration, the activity of ATPases was lower. These results strongly support a positive correlation of microsomal $Ca^{2+}-ATPase$ to the $InsP_{3}$ receptors in epithelial microsomes.

• BMB Reports
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• v.29 no.1
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• pp.22-26
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• 1996

Agents that activate or inhibit the $Ca^{2+}$ release channel in cardiac sarcoplasmic reticulum (SR) were tested for their abilities to affect the activity of the SR $Ca^{2+}$-ATPase. Vesicles of junctional SR (heavy SR, HSR) from terminal cisternae were prepared from porcine cardiac muscle by density gradient centrifugation. The steady-state activity of $Ca^{2+}$-ATPases in intact HSR vesicles was/$347{\pm}5\;nmol/min{\cdot}mg$ protein (${\pm}$ SD). When the HSR vesicles were made leaky, the activity was increased to $415{\pm}5\;nmol/min{\cdot}mg$ protein. This increase is probably due to the uncoupling of HSR vesicles. Caffeine (10 mM), an agonist of the SR $Ca^{2+}$ release channel, increased $Ca^{2+}$-ATPase activity in the intact HSR vesicle preparation to $394{\pm}30\;nmol/min{\cdot}mg$ protein. However, caffeine had no significant effect in the leaky vesicle preparation and in the purified $Ca^{2+}$-ATPase preparation. The effect of caffeine on SR $Ca^{2+}$-ATPase was investigated at various concentrations of $Ca^{2+}$. Caffeine increased the pump activity over the whole range of $Ca^{2+}$ concentrations, from $1\;{\mu}M$ to $250\;{\mu}M$, in the intact HSR vesicles. When the SR $Ca^{2+}$-ATPase was inhibited by thapsigargin, no caffeine effect was observed. These results imply that the caffeine effect requires the intact vesicles and that the increase in $Ca^{2+}$-ATPase activity is not due to a direct interaction of caffeine with the enzyme. We propose that the activity of SR $Ca^{2+}$-ATPase is linked indirectly to the activity of the $Ca^{2+}$ release channel (ryanodine receptor) and may depend upon the amount of $Ca^{2+}$ released by the channels.

• The Korean Journal of Zoology
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• v.20 no.2
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• pp.101-107
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• 1977

The effects of sodium azide, cAMP, G-strophanthin and dicumarol on the ATP-ase activity and Ca uptake of the fragmented sarcoplasmic reticulum of skeletal muscle were studied and the effects were compared with respect to the enzymatic activity and Ca transport. Sodium azide (0.05 mM) and G-strophanthin (0.25mM) caused no inhibition on either ATPase activity or Ca uptake. cAMP($1\\times10^{-6}\\sim5\\times10^{-4}$) had no effect on ATPase activity while inhibited Ca uptake. Dicumarol (0.05 mM) did not inhibit ATPase activity but caused a decreased Ca uptake of heavier fraction (8,000-12,000xG) of the reticulum fragments.

• The Korean Journal of Pharmacology
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• v.2 no.2
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• pp.35-42
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• 1966

The author investigated the effect of $Mg^#$, $Ca^#$, $Na^+$, $K^+$ and creatine phosphate on the ATPase activity of microsomal fraction isolated from rabbit uterus and obtained the following results : 1) The uterine microsomal fraction contained the $Na^+-$ and $K^+-$ activated ATPase in the presence of $Mg^#$. The ATPase activity increased with protein content in the fraction. 2) The maximum ATPase activity was obtained at $Na^+$ and $K^+$ concentraction of 100 mM respectively. 3) In the absence of $Mg^#$, the ATPase was not activated by $Na^+$ and $K^+$, but inhibited. 4) Car stimulated the $Na^+-$ and $K^+-$ activated ATPase in the presence of $Mg^#$. However, in the absence of $Mg^#$, the ATPase was not activated by $Ca^#$. 5) The $K^+-$ activated ATPase activity was greater than the $Na^+-activated$ ATPase under all conditions. 6) The $Na^+-$ and $K^+$ activated ATPase activity was increased by addition of creatine phosphokinase and creatine phosphate to the reaction mixture.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.202-208
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• 1997

In order to investigate the mechanisms of epithelial ion transports, microsomes of soybean roots were prepared and the activity of microsomal ATPases was measured by an enzyme-coupled assay. The effects of various ions were evaluated on the total activity of microsomal ATPases and the average activity was 190 nmol/min/mg protein in the control solution containing $10\;mM\;Na^+\;and\;120\;mM\;K^+$. The activities were increased to 150% and decreased to 63% of the control activity in the solution containing $130\;mM\;K^+$ without $Na^+$ and in the solution containing $130\;mM{\;}Na^+$ without $K^+$, respectively. In general, the activity of microsomal ATPase was increased by$K^+$ in a concentration-dependent manner The activity was also increased at lower pH and relatively higher activities were observed in the pH range of $6{\sim}7$. However, the activity was decreased at weak alkaline $pH\;and{\sim}80%$ of the activity was inhibited at pH 9. Since intracellular $Ca^{2+}$ has been known to control the activity of various enzymes, we have investigated the effects of intra-and extrarnicrosomal $Ca^{2+}$ on the activity of microsomal ATPases. The maximal activity was obtained at the extrarnicrosomal $Ca^{2+}$ concentrations below 1 nM. The activity was gradually decreased by increasing $‘Ca^{2+}’$ concentration and 50% inhibition was observed at ${\sim}500{\;}{\mu}M{\;}Ca^{2+}$. The increase in luminal $Ca^{2+}$ concentration also inhibited the activity of microsomal ATPase. When the influx of external $Ca^{2+}$ was induced by $Ca^{2+}$ ionophore A23187 treatment, the activity was decreased by 30%; however, it was recovered by EGTA-induced chelation of $Ca^{2+}$. These results suggest that the presence of $Ca^{2+}$ regulation sites on both cytoplasmi and luminal sides of microsomal ATPases.

• 한국유가공학회:학술대회논문집
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• 1997.05a
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• pp.23-34
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• 1997

Calcium-stimulated ATPase ($Ca^{2+}$-ATPase) which has optimal pH value at 7.0 was found in the membrane fraction of human milk, and its enzymatic properties were studied. The purified $Ca^{2+}$-ATPase required 0.45 mM Ca ion for maximal activity. Among the nucleosides, $Ca^{2+}$-ATPase showed a higher substrate specificity to ATP and UTP than to CTP and GTP. $Ca^{2+}$-ATPase had apparent Km value of 0.065, and V max of 7.63 mol ATP hydrolyzed/mg pro-tein per min, respectively. $Ca^{2+}$-ATPase was potently inhibited by lanthanide, vanadate, and p-chloromercuribenzoate, and inactivated by EDTA, and CDTA and EGTA, but were unaffected by N-ethylmaleimide, $NaN_3$, ouabain, or oligomycin, and was completely inactivated by heating at $60^{\circ}C$ for 10 min. This enzyme activity was concentrated in the membrane fraction of the cream and skim milk membrane, but not founded in bovine milk.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.4
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• pp.349-355
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• 1990

Actomyosine prepared from Yellowtail fish(seriola quinqueradiata) were stored at $0^{\circ}C$(ice-cooling) -3.5$^{\circ}C$(partial freeaing) and -2$0^{\circ}C$(freezing) Another actomyosin samples were prepared from the fish previously stored at the temperatures for a week as the maximum .Remaining activity of {{{{ {Ca }^{2+ } }}}}-and {{{{ {Mg }^{2+ } }}}}- dependent adenosine triphosphatase(ATPase) activity was measured fronm the actomyosin preparations. Specific activity of {{{{ {Mg }^{2+ } }}}}-ATPase of actomy-osin before storagew was 0.253$\mu$ mole pi/min/mg of protein and it was 1.5 times higher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. The enzyme activities were markedly decreased during early period of storage. However no significant differences in the enzyme activity were revealed among the samples stored at different temperature. The enzyme of actomyosin prepared from the fish previously stored at the temperatures for a week revealed an acitivity of 2-3 times higher than that of freezing. Apparent denaturation constant of {{{{ {Mg }^{2+ } }}}} -ATPase of actomyosin was between 0.810-1.139 per day and it was about 1.5 times hgiher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. But the constant of {{{{ {Mg }^{2+ } }}}} ATPase of actomyosin extracted from the fist stored for a week at each temperature was between 0.176-0.356 per day. This constant was 4 times higher than that of {{{{ {Ca }^{2+ } }}}}- ATPase in frozen stored fish. It was presumed from these results that denaturation of ATPase is largely accorded to the structural changes of actomyosin.