• Bulletin of the Korean Chemical Society
• /
• v.6 no.1
• /
• pp.23-29
• /
• 1985

The charge-transfer complexing properties of 1-methyl nicotinamide (MNA), an acceptor, and adenine, a donor, were investigated in water and SDS micellar solutions in relation to the intramolecular interaction in nicotinamide adenine dinucleotide ($NAD^+$). The spectral and thermodynamic parameters of MNA-indole and methyl viologen-adenine complex formations were determined, and the data were utilized to evaluate the charge-transfer abilities of MNA and adenine. The electron affinity of nicotinamide was estimated to be 0.28 eV from charge-transfer energy $of{\sim}300$ nm for MNA-indole. The large enhancement of MNA-indole complexation in SDS solutions by entropy effect was attributed to hydrophobic nature of indole. The complex between adenine and methyl viologen showed an absorption band peaked near 360 nm. The ionization potential of adenine was evaluated to be 8.28 eV from this. The much smaller enhancement of charge-transfer interaction involving adenine than that of indole in SDS solutions was attributed to weaker hydrophobic nature of the donor. The charge-transfer energy of 4.41 eV (280 nm) was estimated for nicotinamide-adenine complex. The spectral behaviors of $NAD^+$ were accounted to the presence of intramolecular interaction in $NAD^+$, which is only slightly enhanced in SDS solutions. The replacement of nicotinamide-adenine interaction in $NAD^+$ by intermolecular nicotinamide-indole interaction in enzyme bound $NAD^+$, and guiding role of adenine moiety in $NAD^+$ were discussed.

• Journal of Plant Biotechnology
• /
• v.37 no.4
• /
• pp.562-566
• /
• 2010

SOD2-transgenic $T_3$ petunia line (A2-36-2-1-1-35) was treated with different levels of methyl viologen (MV) to determine its resistance to oxidative stress. Four (4) levels of MV (0, 100, 200, and $400\;{\mu}M$) were applied. The SOD2-transgenic $T_3$ petunia line exhibited a very significant oxidative stress resistance at the highest MV concentration ($400\;{\mu}M$) treatment compared to non-transgenic plant. RNA and protein expression of SOD2 transgene and higher parenchyma cell density in the transgenic petunias exhibiting resistance to oxidative stress proves its contribution to the expression of its resistance to oxidative stress.

• Bulletin of the Korean Chemical Society
• /
• v.22 no.11
• /
• pp.1192-1196
• /
• 2001

A diaphorase enzyme electrode for the catalytic reduction of NAD+ , the oxidized form of nicotinamide adenine dinucleotide, has been prepared. The enzyme layer grew spontaneously over an aminoethanethiol self assembled monolayer on a go ld plate electrode. The growth was accomplished by simply dipping the electrode covered by the aminoethanethiol monolayer into a solution containing both glutaraldehyde and diaphorase. We suggested that the glutaraldehyde as a cross-linking reagent was attached to the amino groups of the aminoethanethiol monolayer and the diaphorase enzyme molecules were bound to free aldehyde groups of the glutaraldehyde. Further attachments of the enzyme molecules over the bound enzyme molecules continued with the bridging of the glutaraldehyde. In frequency measurements with a quartz crystal microbalance, the frequency decrease was much more than it was for that of the enzyme monolayer formation, and an enzyme layer thicker than a monolayer was formed. The modified electrode was employed to reduce NAD+ , using diffusional methyl viologen as an electron transfer mediator. The NAD+ was electrocatalytically reduced, and the catalytic current was almost equivalent to that with the multilayered electrode of ten enzyme layers.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.7
• /
• pp.563-567
• /
• 1994

The electroreduction of dioxygen at glassy carbon electrodes with irreversible self-assembly of N-hexadecyl-N'-methyl viologen $(C_{16}VC_1)$ proceeds at potentials more positive than those where the reduction occurs at bare electrodes. The electrocatalyzed reduction takes place at potentials well ahead of those where the catalyst is reduced in the absence of dioxygen and the limiting currents observed at rotating disk electrodes did not deviate from the thoretical Levich line up to 6400 rpm, indicating that the electrocatalysis is extremely rapid. The rate constant for the heterogeneous reaction between $C_{16}V^+C_1$ immobilized on the electrode surface and $O_2$ in solution was estimated to be ca. $10^8\;M^{-1}s^{-1}$. The half-wave potential of dioxygen reduction was independent of solution pH.

• Bulletin of the Korean Chemical Society
• /
• v.5 no.5
• /
• pp.182-187
• /
• 1984

The polarographic and conductometric studies of methyl viologen $(MV^{++})$ solutions with varying concentration of sodium dodecyl sulfate (SDS) showed strong association of $MV^{++}$ and its cationic radical, $MV^+$., with SDS below the critical micelle concentration. The stoichiometries of these associations were found to be their electric charge ratios. Both electrostatic and hydrophobic interactions were found to contribute to the associations. The formation constant of$MV^+.DS^-$ in 0.1 M NaCl was $7{\times}10^3M$. The $MV^{++}$-SDS association was observed to be cooperative leading to formation of large aggregates. In the presence of $MV^{++}$, the micellization of SDS was formation of SDS homo-micelle without direct involvement of $MV^{++}$.

• 한국석유지질학회:학술대회논문집
• /
• autumn
• /
• pp.45-45
• /
• 2000

• Bulletin of the Korean Chemical Society
• /
• v.12 no.6
• /
• pp.593-594
• /
• 1991

• Bulletin of the Korean Chemical Society
• /
• v.15 no.3
• /
• pp.181-183
• /
• 1994

• Bulletin of the Korean Chemical Society
• /
• v.15 no.3
• /
• pp.190-191
• /
• 1994

• Bulletin of the Korean Chemical Society
• /
• v.11 no.3
• /
• pp.170-171
• /
• 1990