• Title, Summary, Keyword: ATP

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Differential Changes of ATP-sensitive Potassium Channel Current after Hypoxia-reperfusion Treatment in Mouse Neuroblastoma 2a (N2a) Cell

  • Park, Ji-Ho
    • The Korean Journal of Physiology and Pharmacology
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    • v.6 no.4
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    • pp.183-186
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    • 2002
  • Ischemic damage is one of the most serious problems. The openers of KATP channel have been suggested to have an effect to limit the ischemic damage. However, it is not yet clear how KATP channels of a cell correspond to hypoxic damage. To address the question, N2a cells were exposed to two different hypoxic conditions as follows: 6 hours hypoxia followed by 3 hours reperfusion and 12 hours hypoxia followed by 3 hours reperfusion. As the results, 6 hours hypoxic treatment increased glibenclamide- sensitive basal $K_{ATP}$ current activity (approximately 6.5-fold at 0 mV test potential) when compared with nomoxic condition. In contrast, 12 hours hypoxic treatment induced a relatively smaller change in the $K_{ATP}$ current density (2.5-fold at 0 mV test potential). Additionally, in experiments where $K_{ATP}$ channels were opened using diazoxide, the hypoxia for 6 hours significantly increased the current density in comparison to control condition (p<0.001). Interestingly, the augmentation in the $K_{ATP}$ current density reduced after exposure to the 12 hours hypoxic condition (p<0.001). Taken together, these results suggest that $K_{ATP}$ channels appear to be recruited more in cells exposed to the 6 hours hypoxic condition and they may play a protective role against hypoxia-reperfusion damage within the time range.

Efficiency Analysis of fermentation Process on Available Electron Balance (Available Electron Balance에 의한 발효과정의 에너지효율)

  • Lee, Kyung-Hee;Kang, Woo-Kyu;Kim, Byung-Woo
    • Microbiology and Biotechnology Letters
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    • v.16 no.2
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    • pp.85-91
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    • 1988
  • Energy efficiency of bacterial cell mass and product formation from cellulose using Ruminococcus albus and Ruminococcus flavefaciens with application of available electron balance were discussed. Values of true growth yield, η$_{max}$ and η$^{max}_{th}$ and maintenance coefficient, m$_{e}$, were estimated us-ing experimental data, and the results were compared with estimates obtained from theoretical ap-proach. Experimental values were similar in magnitude to theoretical values in $Y^{max}_{ATP}$= 10.5 g cells/ mole ATP. Therefore, $Y^{max}_{ATP}$ values of Ruminococcus albus and Ruminocoecus flavefaciens were considered similar to 10.5 g cells/mole ATP.

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Effect of Various Receptor Blockers on the Action of Adenosine Triphosphate on Uterine Smooth Muscle Motility in Immature Pig (미성숙 돼지 자궁 평활근의 운동성에 대한 Adenosine Triphosphate의 작용에 있어서 수종의 Receptor 차단제의 영향)

  • Kim, Joo-heon;Kwun, Jong-kuk;Kim, Yong-keun
    • Korean Journal of Veterinary Research
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    • v.27 no.2
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    • pp.201-206
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    • 1987
  • This study was carried out to investigate the action of ATP, which has been known as the neurotransmitter of noncholinergic- and nonadrenergic-nerve, on the motility of immature pig uterine smooth muscle. The results were summarized as follows; 1. The contraction and the contractile responses caused by ATP were increased in a dose-dependent manner between the concentration of ATP $10^{-6}M$ and $10^{-3}M$. The maximal contractile effect was appeared at the concentration of ATP $10^{-3}M$ and it was 70.2% of 100mM K contraction. 2. The contractile responses induced by ATP ($10^{-4}M$) were not blocked by the pretreatment with cholinergic receptor blocker, atropine ($10^{-6}M$). 3. The contractile responses induced by ATP ($10^{-4}M$) were not blocked by pretreatment with ${\alpha}$-adrenergic receptor blocker, phentolamine ($10^{-6}M$) and ${\beta}$-adrenergic receptor blocker, propranolol ($10^{-6}M$). 4. The contractile response induced by ATP ($10^{-4}M$) was not blocked by the pretreatment with $H_1-receptor$ blocker, pyrilamine ($10^{-6}M$) and $H_2-receptor$ blocker, cimetidine ($10^{-6}M$).

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Effect of Propofol, an Intravenous Anesthetic Agent, on $K_{ATP}$ Channels of Pancreatic ${\beta}-cells$ in Rats

  • Park, Eun-Jee;Song, Dae-Kyu;Cheun, Jae-Kyu;Bae, Jung-In;Ho, Won-Kyung;Earm, Yung-E
    • The Korean Journal of Physiology and Pharmacology
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    • v.4 no.1
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    • pp.25-31
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    • 2000
  • ATP-sensitive potassium channels ($K_{ATP}$ channels) play an important role in insulin secretion from pancreatic beta cells. We have investigated the effect of propofol on $K_{ATP}$ channels in cultured single pancreatic beta cells of rats. Channel activity was recorded from membrane patches using the patch-clamp technique. In the inside-out configuration bath-applied propofol inhibited the $K_{ATP}$ channel activities in a dose-dependent manner. The half-maximal inhibition dose (ED50) was $48.6{\pm}8.4\;{\mu}M$ and the Hill coefficient was $0.73{\pm}0.11.$ Single channel conductance calculated from the slope of the relationship between single channel current and pipette potential $(+20{\sim}+100\;mV)$ was not significantly altered by propofol $(control:\;60.0{\pm}2.7\;pS,\;0.1\;mM\;propofol:\;58.7{\pm}3.5\;pS).$ However, mean closed time was surely increased. Above results indicate that propofol blocks the $K_{ATP}$ channels in the pancreatic beta cells in the range of its blood concentrations during anesthesia, suggesting a possible effect on insulin secretion and blood glucose level.

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Diagnostic test for bovine mastitis by the determination of ATP based on firefly bioluminescence (Bioluminescence 반응에 의한 ATP 측정을 이용한 젖소 유방염 진단에 관한 연구)

  • Kim, Tae-jong;Kim, Jong-bae;Lee, Seoung-bae;Jeon, Young-soo
    • Korean Journal of Veterinary Research
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    • v.29 no.3
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    • pp.383-391
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    • 1989
  • This study was carried out to diagnostic test for bovine mastitis by the determination of adenosine triphosphate (ATP) based on firefly bioluminescence. The results obtained are follow; 1. The infection rate of bovine mastitis investigated with 521 cows in 47 dairy farms were found to be 3.6% of clinical form and 44.1% of subclinical form according to the degree of infection. 2. The light yield produced in firefly bioluminescence system was proportional to the concentration of ATP giving stright line within the range of 100PM~1uM. 3. When the number of somatic cell in milk was determined by the ATP assay and compared with three conventional methods such Fossomatic, California mastatic test (CMT), and rolling ball viscometer (RBV), it was shown that r=0.92 for Fossomatic, 0.63 for CMT and 0.7 for RBV. 4. The microorganisms causing mastitis were isolated Staphylococcus sp. (53.3%), Streptococcus sp. (17.9%), Micrococcus sp. (13.5%), Gram negative bacilli (6.3%), Gram positive bacilli (5.5%) and Yeast-like fungi (5.4%). 5. The endogeneous ATP levels of bacteria in a raw milk determined by the firefly bioluminescence system and compared with the results of the conventional methods. The correlation was 0.88 for raw milk.

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Relationship of Action of Adenosine Triphosphate and Prostaglandin $F_{2{\alpha}}$ on Uterine Smooth Muscle Motility in Immature Pig (미성숙 돼지 자궁 평활근의 운동성에 대한 Adenosine Triphosphate와 Prostaglandin $F_{2{\alpha}}$ 작용의 관계)

  • Kim, Joo-Heon;Kwun, Jong-Kuk;Kim, Yong-Keun
    • The Korean journal of physiology & pharmacology
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    • v.22 no.1
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    • pp.31-39
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    • 1988
  • This study was carried out to investigate the action of adenosine triphosphate (ATP) on the motility of immature pig uterine smooth muscle. ATP appeared contractile responses in a dose-dependent manner, showing the maximal contraction at the concentration of $10^{-3}M$ in the uterine smooth muscle strip. The contractile responses by $ATP(10^{-4}M)$ were not affected by atropine $(10^{-6}M)$, phentolamine $(10^{-6}M)$, propranolol $(10^{-6}M)$, pyrilamine $(10^{-6}M)$, cimetidine $(10^{-6}M)$, and theophyulline $(5{\times}10^{-5}M)$, but were inhibited uncompetitively by quinidine. The effects of these drugs on the contractile responses by prostaglandin $F_{2{\alpha}}(PGF_{2{\alpha}})$ were also comparable to those observed with ATP. When muscle strips were pretreated with indomethacin $(5{\times}10^{-5}M)$ for 20 min., the contractile responses by $ATP(10^{-4}M)$ were completely inhibited. But the contractile responses by $PGF_{2{\alpha}}$ were not affected by indomethacin. These results suggest that ATP elicited the contraction through noncholinergic- and nonadrenergic-receptor mediated by prostaglandin $F_{2{\alpha}}$ in pig uterine smooth muscle.

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Delivery System of Daunorubicin by Red Blood Cells (적혈구를 이용한 Daunorubicin의 배송시스템)

  • Ham, Seong-Ho;Song, Kyung;Ko, Gun-Il;Kim, Jae-Baek;Sohn, Dong-Hwan
    • Journal of Pharmaceutical Investigation
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    • v.24 no.3
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    • pp.131-137
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    • 1994
  • Drug delivery system by the use of red blood cells was established to sustain the release of drugs in the circulatory system by the intravenous injection. The entrapment method by the preswelling technique was re-examined and evaluated for searching the new entrapping conditions without hemolysis. The addition of 4 volume of $0.6{\times}\;hank's$ balanced salt solution (HBSS) into 1 volume of 50% red blood cells suspension did not induce the hemolysis and change the hematocrit level in this experimental condition (within 15 min). Most of daunorubicin could be entrapped into red blood cells within 15 min. While the intracellular adenosine triphosphate (ATP) level followed by the entrapment was reduced to 86% of normal ATP level, the membrane fluidity and the shape factor of red blood cells were not altered. The release rate of daunorubicin from red blood cells was affected by the hemolysis under this condition. To maintain the intracellular ATP in red blood cells, the new reaction buffer was made With the addition of ATP and sodium pyruvate during the entrapment procedure because the hemolysis during the release test would reflect the loss of intracellular ATP that might result in the decrease of the viability in vivo. The addition of ATP raised the intracellular ATP level, which protect the hemolysis during the release test.

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Catalytic and Structural Properties of Pyridoxal Kinase

  • Cho, Jung-Jong;Kim, Se-Kwon;Kim, Young-Tae
    • BMB Reports
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    • v.30 no.2
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    • pp.125-131
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    • 1997
  • This work reports studies of the catalytic and structural properties of pyridoxal kinase (ATP: pyridoxal 5' -phosphotransferase, EC. 2.7.1.35), Pyridoxal kinase catalyzes the phosphorylation of vitamin $B_6$ (pyridoxal, pyridoxamine, pyridoxine) using ATP-Zn as a phosphoryl donor. The enzyme purified from brain tissues is made up of two identical subunits of 40 kDa each. Native enzyme was inhibited by a substrate analogue, pyridoxal-oxime. Limited chymotrypsin digestion of pyridoxal kinase yields two fragments of 24 and 16 kDa with concomitant loss of catalytic activity. These fragments were isolated by DEAE ion exchange chromatography and used for binding studies with fluorescent ATP and pyridoxal analogues. The spectroscopic properties of both fluorescent pyridoxal analogue and Anthraniloyl ATP (Ant-ATP) bound to the 24 kDa fragment are indistinguishable from those of both pyridoxal analogue and Ant-ATP bound to the native pyridoxal kinase, respectively. The small 16 kDa fragment, generated by proteolytic cleavage of the kinase, does not bind any of the substrate analogues. Binding characteristics of Ant-ATP were extensively studied by measuring the changes in fluorescence spectra at various conditions. From the results presented herein, it is postulated that the structural domain associated with catalytic activity comprises approximately one-half of the molecular mass of pyridoxal kinase (24 kDa). whereas the remaining portion (16 kDa) of the enzyme contains a regulatory binding domain.

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The Growth Yield of Desulfovibrio desulfuricans M6 on Different Substrates

  • Park, Doo-Hyun;Shin, Chul-Su;Kim, Byung-Hong;Shin, Pyung-Kyun
    • Journal of Microbiology and Biotechnology
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    • v.6 no.4
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    • pp.232-237
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    • 1996
  • Growth yield of Desulfovibrio desulfuricans M6 was measured using different substrates. The cell yield of fermentative growth on pyruvate was 6.22 g cell $mol^{-l}$ pyruvate. Since 1 ATP is available from substrate-level phosphorylation from the oxidation of pyruvate to acetate, $Y_{ATP}$ of the bacterium should be the same as $Y_{pyruvate}$ (6.22 g cell $mol^{-l}$ ATP). The cell yields of the bacterium on different electron donors were measured with sulfate as the electron acceptor. Cell yields on lactate, pyruvate and $H_2$ were 9.39, 13.76 and 8.45 g cell $mol^{-l}$ substrate, respectively. From these figures ATP available from electron-transport phosphorylation (ETP) of the electron donors used was calculated. ATP produced by ETP of each electron donnor were 1.71 from pyruvate, 1.51 from lactate and 1.76 from $H_2$. These values show that electrons from the oxidation of lactate to pyruvate are consumed to reduce sulfate through a reverse electron transport mechanism requiring 0.2 ATP for each pair of electrons. Based on these results, discussions are made on the electron transport mechanism in the bacterium.

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Effects of Signal Peptide and Adenylate on the Oligomerization and Membrane Binding of Soluble SecA

  • Shin, Ji-Yeun;Kim, Mi-Hee;Ahn, Tae-Ho
    • BMB Reports
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    • v.39 no.3
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    • pp.319-328
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    • 2006
  • SecA protein, a cytoplasmic ATPase, plays a central role in the secretion of signal peptide-containing proteins. Here, we examined effects of signal peptide and ATP on the oligomerization, conformational change, and membrane binding of SecA. The wild-type (WT) signal peptide from the ribose-binding protein inhibited ATP binding to soluble SecA and stimulated release of ATP already bound to the protein. The signal peptide enhanced the oligomerization of soluble SecA, while ATP induced dissociation of SecA oligomer. Analysis of SecA unfolding with urea or heat revealed that the WT signal peptide induces an open conformation of soluble SecA, while ATP increased the compactness of SecA. We further obtained evidences that the signal peptide-induced oligomerization and the formation of open structure enhance the membrane binding of SecA, whereas ATP inhibits the interaction of soluble SecA with membranes. On the other hand, the complex of membrane-bound SecA and signal peptide was shown to resume nucleotide-binding activity. From these results, we propose that the translocation components affect the degree of oligomerization of soluble SecA, thereby modulating the membrane binding of SecA in early translocation pathway. A possible sequential interaction of SecA with signal peptide, ATP, and cytoplasmic membrane is discussed.