• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2173-2179
• /
• 2017

The intracytoplasmic membrane of Rhodobacter sphaeroides readily vesiculates when cells are lysed. The resulting chromatophore membrane vesicle (CMV) contains the photosynthetic machineries to synthesize ATP by ATPase. The light-dependent ATPase activity of CMV was lowered in the presence of $O_2$, but the activity increased to the level observed under anaerobic condition when the reaction mixture was supplemented with ascorbic acid (${\geq}0.5mM$). Cell lysis in the presence of biotinyl cap phospholipid (bcp) resulted in the incorporation of bcp into the membrane to form biotinylated CMV (bCMV), which binds to streptavidin resin at a ratio of approximately $24{\mu}g$ bacteriochlorophyll a/ml resin. The ATPase activity of CMV was not affected by biotinylation, but approximately 30% of the activity was lost by immobilization to resin. Interestingly, the remaining 70% of ATPase activity stayed constant during 7-day storage at $4^{\circ}C$. On the contrary, the ATPase activity of bCMV without immobilization gradually decreased to approximately 40% of the initial level in the same comparison. Thus, the ATPase activity of CMV is sustainable after immobilization, and the immobilized bCMV can be used repeatedly as an ATP generator.

• Biomedical Science Letters
• /
• v.6 no.3
• /
• pp.165-170
• /
• 2000

Vacuolar (H$^{+}$)-ATPase (V-ATPase) is an intracellular protein which consists of multiple subunits. It carries out acidification by pumping protons in the cell. This enzyme has also been found in the synaptic vesicles and may play an important role in the neurotransmission. We cloned cDNA fragments encoding the 16 kDa subunit of V-ATPase from the rat brain by RT-PCR and PCR using total RNA or recombinant phage DNA as templates. They contained the full coding sequences (468 bp) and one nucleotide at 3' region turned out to be different (A to C) when compared to the liver counterpart. However, this polymorphic difference did not cause any significant change in the primary structure of the protein because both GCA and GCC code for alanine. Our study would contribute to the understanding of the function of 16 M)a V-ATPase in the brain and of the mechanisms of neurotransmission.

• BMB Reports
• /
• v.29 no.1
• /
• pp.22-26
• /
• 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
• /
• v.37 no.4
• /
• pp.531-537
• /
• 1994

Partial internal amino acid sequences of the 15S ATPase from chick skeletal muscle were determined and found to be identical to the corresponding regions of the Mg2+_ATPase from Xenopus laevis oocytes, that is a close homolog of N-ethvlmaleimide-sensitive factor (called NSF) in hamster and Sec18p in yeast, both of which are believed to plaN an essential role in vesicle fusion in secretory process. Thus, the 15S Arpase in chick skeletal muscle maw also belong to a protein family of the "vesicle fusion proteins". Unlike the Mg2'-Afpase with an isoelectric point (pl) of 5.5, however, the 15S Arpase was separated into four spots with pls of 4.9,6.4 and 6.9 upon analysis by twoiimensional gel electrophoresis. In addition, the anti-15S ATPase IgG was found to be capable of interacting with the 265 protease complex upon analysis by immunoprecipitation. Moreover, immunoblot analysis revealed that the anti-155 Arpase IgG recognizes three subunits, ko of which show the same mobilities as the 510-kDa subunit 4 and 48-kDa subunit 7 of the 26S protease complex that are known to contain a highly consented ATP-binding motif. These results surest that a common antigenic site, likely the consensus nucleotide-binding site, exists in the 15S ATPase and the 26S pretense complex and hence both the enzymes maw also be related ATPases.d ATPases.

• The Korean Journal of Pharmacology
• /
• v.30 no.1
• /
• pp.117-124
• /
• 1994

Phospholamban is the regulator of $Ca^{2+}-ATPase$ in cardiac sarcoplasmic reticulum(SR). The mechanism of regulation appears to involve inhibition by dephosphorylated phospholamban. Phosphorylation of phospholamban relieves this inhibition. Recently, there has been a report that the cytoplasmic domain (amino acids 1-25) of phospholamban is insufficient to inhibit the $Ca^{2+}$ pump. To explore the domains of phospholamban responsible for $Ca^{2+}-ATPase$ inhibitory activity, we examined the effect of a synthetic phospholamban peptide consisting of amino acid residues 1-25 on $Ca^{2+}$ uptake by reconstituted skeletal SR $Ca^{2+}-ATPase$. The $Ca^{2+}-ATPase$ of skeletal SR was purified and reconstituted in proteoliposomes containing phosphatidylcholine (PC) or phosphatidylcholine: phosphatidylserine (PC:PS). Inclusion of a phospholamban peptide in PC proteoliposomes was associated with significant inhibition of the initial rates of $Ca^{2+}$ uptake at pCa 6.0, and phosphorylation of this peptide by the catalytic subunit of cAMP-dependent protein kinase reversed the inhibitory effect on the $Ca^{2+}$ pump. Similar effects of phospholamban peptide were also observed using PC:PS proteoliposomes. Based on these results, we could conclude that the cytoplasmic domain of phospholamban, containing the phosphorylation sites, by itself is sufficient to inhibit the $Ca^{2+}$ pump of SR.

• The Korean Journal of Pharmacology
• /
• v.26 no.1
• /
• pp.35-49
• /
• 1990

A highly purified $(Na^+,\;K^+)-ATPase$ from the rectal gland of Squalus acanthias and from the electric organ of Electrophorus electricus has been used to raise antibodies in rabbits. The 97,000 dalton catalytic subunit and glycoprotein derived from the rectal gland of spiny shark were also used as antigens. The two $(Na^+,\;K^+)-ATPase$ holoenzymes and the two shark subunits were antigenic. In Ouchterlony double diffusion experiments, these antibodies formed precipitation bands with their antigens. Antibodies prepared against the two subunits of shark holoenzyme also formed precipitation bands with their antigens and shark holoenzyme, but not with eel holoenzyme. These observations are in good agreement with inhibitory effect of these antibodies on the catalytic activity of $(Na^+,\;K^+)-ATPase$ both from the shark and the eel, since there is very little cross-reaction between the shark anticatalytic subunit antibodies and the eel holoenzyme. The maximum antibodies titer of the anticatalytic subunit antibodies is found to be 6 weeks after the initial single exposure to this antigen. Multiple injections of the antigen increased the antibody titer. However, the time required to produce the maximum antibody titer was approximately the same. These antibodies also inhibit catalytic activity of $(Na^+,\;K^+)-ATPase$ vesicles reconstituted by a slow dialysis of cholate after solubilization of the enzyme in a presonicated mixture of cholate and phospholipid. In these reconstituted $(Na^+,\;K^+)-ATPase$ vesicles, effects of these antibodies on the fluxes of $Na^+$, $Rb^+$, and $K^+$ were investigated. Control or preimmune serum had no effect on the influx of $^{22}Na^+$ or the efflux of $^{86}Rb^+$. Immunized sera against the shark $(Na^+,\;K^+)-ATPase$ holoenzyme, its glycoprotein or catalytic subunit did inhibit the influx of $^{22}Na^+$ and the efflux of $^{86}Rb^+$. It was also demonstrated that these antibodies inhibit the coupled counter-transport of $Na^+$ and $K^+$ as studied by means of dual labeling experiments. However, this inhibitory effect of the antibodies on transport of ions in the $(Na^+,\;K^+)-ATPase$ vesicles is manifested only on the portion of energy and temperature dependent alkali metal fluxes, not on the portion of ATP and ouabain insensitive ion movement. Simultaneous determination of effects of the antibodies on ion fluxes and vesicular catalytic activity indicates that an inhibition of active ion transport in reconstituted $(Na^+,\;K^+)-ATPase$ vesicles appears to be due to the inhibitory action of the antibodies on the enzymatic activity of $(Na^+,\;K^+)-ATPase$ molecules incorporated in the vesicles. These findings that the inhibitory effects of the antibodies specific to $(Na^+,\;K^+)-ATPase$ or to its subunits on ATP and temperature sensitive monovalent cation transport in parallel with the inhibitory effect of vesicular catalytic activity by these antibodies provide direct evidence that $(Na^+,\;K^+)-ATPase$ is the molecular machinery of active cation transport in this reconstituted $(Na^+,\;K^+)-ATPase$ vesicular system.

• Applied Microscopy
• /
• v.18 no.2
• /
• pp.187-204
• /
• 1988

The present experiment was performed to investigate the acute and subacute effect of lead acetate on ultrastructural and biochemical changes in mouse diencephalon. In acute case, mouse were peritoneally injected with lead acetate at a dose of 0.26 mmole/kg body weight, and after treatment, mouse were sacrificed at time intervals of 12, 24, 48, and 96 hours. In subacute case, mouse were injected at doses of 0.07 mmoie/kg B. W. and 0.13 mmole/kg B.W. once at two days, and after treatment, mouse wee sacrificed at 1 week, 2 weeks, and 3 weeks. It was observed that after acute treatment, changes composed of increased monoamine oxidase activity, $Na^{+}-K^{+}$ ATPase activity, decreased $Mg^{2+}$-APTase activity, wrinkled myelin, swollen Golgi apparatus and more dense synaptic vesicle in nerve terminal. After subacute treatment, decreased monoamine oxidase activity, increased $Mg^{2+}$-ATPase, $Na^{+}-K^{+}$ ATPase, lose of myelin, uneven mitochondrial distribution, synaptic vesicular density and edema, but at a higher dose the effect was more severe. Therefore, lead acetate caused abnormal change of diencephalon, and at a subacute, it appears metal accumulative toxicity.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.6
• /
• pp.378-385
• /
• 1997

Cation motive ATPases on cell membranes of Helicobacter pylori were investigated using everted membrane vesicles. Latent ATPases could be ascertained from aggregated vesicle using N, N-dimethylformamide (DMF) and Triton X-100. By contrast, ultrasonication or chloroform treatments caused membranes to be disrupted, resulting in an alteration of sensitivities against azide or vanadate. Considerable amounts of vanadate-sensitive enzymes were identified from vesicle micelles, prepared by the dilution method. These were activated in the presence of either $Ni^{2+}\;or\;NH_4^+$. From studies employing H. pylori intact cell systems, we found that ATPase expression of this bacterium was markedly dependent upon air composition. It was interesting that cellular expression of $Ni^{2+}$- or $NH_4^{+}$-motive ATPases was significantly affected by extracellular pH, suggesting that these unique enzymes may physiologically be involved in cellular $Ni^2$ import and $NH_4^+$ export, respectively.

• Korean Journal of Pharmacognosy
• /
• v.43 no.1
• /
• pp.72-78
• /
• 2012

Alnus japonica Steud (A. japonica) have long been used in the traditional medicine for gastric disorder, hepatitis and fatty liver in Korea. Antiulcer effects of A. japonica hot water extract (AJ ext) were evaluated by in vitro antibacterial activity against H. pylori, by the inhibitory action against the in vitro gastric $H^+/K^+$-ATPase and using rat models of gastric mucosal damage and gastric ulcer induced by HCl-ethanol, indomethacin, and restraint and water-immersion stress. For the determination of antibacterial activity of AJ ext against H. pylori, the activity of urease which released from H. pylori was measured in culture. AJ ext showed weak antibacterial activity against H. pylori with the growth inhibitions of 37% and 61% by adding final concentrations of 500 and $1000{\mu}g/ml$ culture, respectively at 24 h. To observe the inhibitory activity of AJ ext against the $H^+/K^+$-ATPase in hog gastric membrane vesicle, $IC_{50}$ value of AJ ext was $806.3{\mu}g/ml$. Pretreatment of AJ ext (200, 500 mg/kg, p.o.) prevented in a dose-dependent manner the acute gastritis in HCl-ethanol model and the formation of gastric ulcer in indomethacin model and restraint and water-immersion stress model. These results suggest that the AJ ext can be used for prevention and treatment of gastric mucosal damage and ulcers induced by various stress.

• Journal of Food Hygiene and Safety
• /
• v.8 no.4
• /
• pp.195-204
• /
• 1993

Basolateral and brush border membrane (BLM and BBM) vesicles of renal proximal tubules were prepared from adult male New Zealand White rabbits to evaluate as a potential model for assessment of nephrotoxicity. PAH uptakes using BLMV, glucose and leucine uptakes using BBMV were measured in the rabbits treated cephaloridine. In addition, urinalysis and histopathological studies were performed to investigate the correlationship with membrane vesicle uptakes. The results were as follows: (1) the activite of Na+, K+ -ATPase was enriched 12.3-fold in vasolateral memvrane vesicles (BLMV) and the specific activity of alkaline phosphatase in purified brush border memvrane vesicles (BBMV) was enriched 10.1-fold compared with each of microsomal homogenate. (2) In the uptake experiments, cephaloridine decreased initial and probenecid-sensitive PAH uptakes in BLMV. (3) Cephaloridine tested decreased initial and phlorizin-sensitive glucose uptakes in BBMV. (4) Cephaloridine tested decreased initial and Na+-dependent leucine uptakes in BBMV. (5) Cephaloridine tested significantly increased the urinary excretion of glucose and activity of ${\gamma}$-GTP. (6) Cephaloridine tested caused moderate necrotic changes in renal tubular cells and formation of urinary cast in the lumina of Henle's loop and collecting tubules besides the swelling of renal tubules.