• Applied Biological Chemistry
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• v.30 no.4
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• pp.357-363
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• 1987

The transition temperature of respiratory activity of mitochondria isolated from panicles of rice plant was measured with 41 varieties bred in Korea, which had been agronomically classified into five groups based on their relative cold-tolerance; S (strong cold-tolerance), S-M (moderate to strong cold-tolerance), M (moderate cold-tolerance), M-W (moderate to weak cold-tolerance) and W (weak cold-tolerance). The temperature was found to be $11.5{\sim}13.5^{\circ}C$ for group S, $13.5{\sim}16^{\circ}C$ for group S-M, $16{\sim}17^{\circ}C$ for group M, $17{\sim}18^{\circ}C$ for group M-W, and ${\geq}18^{\circ}C$ for group W respectively with a few exceptions of minor deviation, demonstrating a close correlation between the transition temperature and the chilling susceptivity of a variety. This observation supports the suggestion that the transition temperature of respiratory activity of panicles be adopted as a reliable index for grading a rice variety as to its overall cold tolerance. Also studied is on the methodology for measurement of the transition temperature in the aspect of analytical biochemistry. In addition to the usual polarographic method, a spectrophotometric method which is based on the enzymatic assay of membrane-bound cytochrome C oxidase was examined. This enzyme was found previousely and confirmed again in the present work to be a key factor governing the respiratory trantion at least in plant mitochondria. The optical method was turned out to be very successful, although it was a little more complicate and time-consuming than the electrochemical method.

• Journal of the Korean Chemical Society
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• v.18 no.3
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• pp.202-209
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• 1974

Polarographic behaviors of copper and cadmium complexes with 2,2'-bipyridine and ethylenediamine in acetonitrile have been investigated by the DC and AC polarography. The reduction processes are estimated as follows; $Cu(II)-bipy. \;complex\;{\longrightarrow^{e^-}_{E_{1/2}\risingdotseq+0.1V}}\;Cu(I)-bipy.\;complex\;{\longrightarrow^{e^-}_{E_{1/2}=-0.43V}}\;Cu(Hg)$$Cu(II)-en.\;complex\;{\longrightarrow^{e^-}}\;Cu(I)-en.\;complex\;{times}\;{\longrightarrow^{e^-}_{E_{1/2}=-0.56V}}\;Cu(Hg)$$Cu(II)-bipy. \;complex\;{\longrightarrow^{e^-}_{E_{1/2}=-0.57V}}\;Cu(I)-bipy.\;complex\;{\longrightarrow^{2e^-}_{E_{1/2}=-0.97V}}\;Cd(I)-bipy\;complex$$Cu(II)-en.\;complex\;{\longrightarrow^{e^-}_{E_{1/2}=+0.05V}\;Cu(I)-en.\;complex{\longrightarrow^{e^-}_{E_{1/2}=-0.92V}}\;Cu(Hg)$ The limiting currents of all steps are controlled by diffusion. The number of ligand and the dissociation constant for Cu(Ⅰ)-bipy. complex were found to be n = 2 and $K_d=(1.5{\pm}0.1){\times}10^{-7}$, respectively.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.197-204
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• 1985

The dependence of polarographic parameters on pressure and temperature for the reduction of 2.0 ${\times}\;10^{-4}$M 1-(2-pyridylazo)-2-naphthol (PAN) and 5.0 ${\times}\;10^{-4}$M 4-(2-pyridylazo)-resorcinol(PAR) in buffered methanol-water mixed solution at the dropping mercury electrode, has been discussed. In this experiment the temperature is varied from 25$^{\circ}C$ to 35$^{\circ}C$ and the pressure is ranging from 1 atmosphere to 1,800 atmospheres. The reduction half-wave potentials are shifted to the more positive potentials with increase in pressure. The diffusion currents of two depolarizers become considerably larger with increase in pressure from 1 atmosphere to about 1,000 atmospheres but are getting smaller above 1,000 atmospheres. The slopes of log plot become much larger with increase in pressure, which indicates the more irreversible reduction. The reduction currents of two depolarizers are found to be diffusion controlled over all pressure ranges. The linear relationships between diffusion current and the concentration of two depolarizers are good agreement over all pressure ranges (1 atm∼1,800atm.).

• Journal of the Korean Society of Visualization
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• v.14 no.1
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• pp.51-56
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• 2016

Oxygen is a key factor in aerobic reactions and most biological activities. Visualization of oxygen distribution of a chemical process or biological system has been a very challenging object despite of its significance and potential impact. To monitor and visualize the spatial distribution of oxygen concentration, various techniques such as electro-chemical probe, polarographic electrode, LIF(laser-induced fluorescence) and so on have been introduced. Oxygen planar optode which utilizes the oxygen quenching of fluorescence light is one of the currently available methods for time-resolved visualization of oxygen distribution on a planar surface. In this study, we utilized VisiSens oxygen planar optode system to visualize the spatial distribution of oxygen concentration on leaves of Korean azalea. As a result, temporal variation of oxygen concentration distribution caused by respiratory activity of the leaf could be quantitatively monitored.

• Journal of the Korean Chemical Society
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• v.11 no.2
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• pp.63-69
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• 1967

The stability constants of lead acetato conplexes were evaluated in various ionic strengths (2.00, 1.00, and 0.75), and at various temperature (15, 20, 25, 30, and $35^{\circ}C$), respectively, by the polarographic and potentiometric method of which Hume and Leden had described. The existence of three complex ions, $PbAc^+$, $PbAc_2$, and $PbAc_3^-$ have been shown in the range of concentration of 0~0.8 mole acetate ion. Referring to values obtained, we have derived the following empirical formula with the stability constant (Kijk), ternperature (Tk) and ionic strength (${\mu}j$). log Kijk = (Ai/${\mu}j^3$+ Bi) / Tk + Ci/${\mu}j^3$ + Di . The deduced and observed stability constants are matched in 5% for the K, and $K_3$, and 20% for the $K_2$.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.30-36
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• 1988

The effect of high pressure on the stability of copper(II), cadmium(II) and zinc (II) complex ions with ethylenediamine, propylenediamine, diethylenetriamine has been investigated polarographically. 0.10M KN$O_3$ solution was used as a supporting electrolyte. The concentration of chelating agents was varied from 0.01M to 1.00M. The dissociation constants of metal complex ions were increased with increasing the pressure from 1 atmosphere to 1,500 atmospheres. The increment of the dissociation constant per unit atmosphere varied from 1.1 ${\times} 10^{-3}$% for Cu(dien)$_2^{2+}$ to 5.0 ${\times} 10^{-3}$ % for Zn(en)$_2^{2+}$.

• Archives of Pharmacal Research
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• v.26 no.11
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• pp.951-959
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• 2003

A series of typical (chlorpromazine, haloperidol and thioridazine) and atypical (risperidone, quetiapine, clozapine and olanzapine) antipsychotics were tested for effects on integrated bioenergetic functions of isolated rat liver mitochondria. Polarographic measurement of oxygen consumption in freshly isolated mitochondria showed that electron transfer activity at respiratory complex I is inhibited by chlorpromazine, haloperidol, risperidone, and quetiapine, but not by clozapine, olanzapine, or thioridazine. Chlorpromazine and thioridazine act as modest uncouplers of oxidative phosphorylation. The typical neuroleptics inhibited NADH-coenzyme Q reductase in freeze-thawed mitochondria, which is a direct measure of complex I enzyme activity. The inhibition of NADH-coenzyme Q reductase activity by the atypicals risperidone and quetiapine was 2-4 fold less than that for the typical neuroleptics. Clozapine and olanzapine had only slight effects on NADH-coenzyme Q reductase activity, even at 200 $\mu$ M. The relative potencies of these neuroleptic drugs as inhibitors of mitochondrial bioenergetic function is similar to their relative potencies as risk factors in the reported incidence of extrapyramidal symptoms, including tardive dyskinesia (TD). This suggests that compromised bioenergetic function may be involved in the cellular pathology underlying TD.

• BMB Reports
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• v.29 no.4
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• pp.300-307
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• 1996

ATP and ADP are potential regulators of mitochondtial respiration and at physiological concentrations they affect the rate of electron transfer between cytochrome c and cytochrome c oxidase. The electron transfer, however, depends on the electrostatic interaction between the two proteins. In order to exclude any nonspecific ionic effects by these polyvalent nucleotides, we used 2'-O-(2,4,6)trinitro(TNP)-derivatives of ATP and ADP which have three orders of magnitude higher affinity for cytochrome c oxidase. A simple titration of the fluorescence intensity of TNP by cytochrome c oxidase showed a binding stoichiometry of 2:1 cytochrome c:cytochrome c oxidase. Higher ionic strength was required for TNP-ATP than for TNP-ADP to be dissociated from cytochrome c oxidase, indicating that the negative charges on the phosphate group are at least partially responsible for the binding. In both spectrophotometric and polarographic assays, addition of ATP (and ADP to a less extent) showed an enhanced cytochrome c oxidase activity. Both electron paramagnetic resonance and fluorescence spectra indicate that there is no Significant change in the cytochrome c-cytochrome c oxidase interaction. Instead, reduction levels of the cytochromes at steadystate suggest that the increased activity of nucleotide-bound cytochrome c oxidase is due to faster electron transfer from cytochrome ${\alpha}$ to cytochrome ${\alpha}_3$, which is known to be the fate limiting step in the oxygen reduction by cytochrome c oxidase.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.596-600
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• 1989

The simple and mixed ligand complexes of cadmium-oxalate-citrate systems have been studied with differential pulse polarography at 25${\circ}$C, in the solution with constant ionic strength, ${\mu}$= 1.0 ($NaNO_3$) and pH 8.0. Using the graphical methods by DeFord-Hume and Schaap-McMasters, the overall stability constants for the mixed ligand complexes, $\beta_{ij}$, were found to be: $log\beta_{11}$ = 4.91, $log\beta_{12}$ = 4.99, and log $log\beta_{21}$ = 5.18, respectively. Various equilibria involved in the mixed system have also been discussed.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.672-676
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• 1993

The complexation of bilirubin with zinc(II) and copper(II) ions was studied spectrophotometrically. In the zinc(II)-bilirubin (Zn-BR) system, complex is formed, but the copper(II) ion oxidizes bilirubin to biliverdin and then to the further oxidation products. The electrochemical reduction behavior of ZN-BR complex has been investigated with DC polarography and cyclic voltammetry. The three polarographic waves were obtained for the reduction of ZN-BR complex in DMF solution. Thde reduction current of the third wave was diffusion current, but that of the first and the second waves contained a little kinetic current.