• Bulletin of the Korean Chemical Society
• /
• v.16 no.2
• /
• pp.112-120
• /
• 1995

The conformational study on malonic acid, hydrogen malonate, malonate, malonyl methyl sulfide, and malonyl methyl sulfide anion, as the model compounds of malonyl-CoA, was carried out using the semiempirical MO methods (MNDO, AM1, and PM3) and hydration shell model. On the whole, the feasible conformations of malonic acid, hydrogen malonate, and malonate seem to be similar to each other. In malonic acid and malonate, two carboxyl groups are nearly perpendicular to the plane of the carbon skeleton, despite of different orientation of two carboxyl groups themselves. In particular, two carboxyl groups of hydrogen malonate are on the plane formed by carbon atoms with an intramolecular hydrogen bond. The calculated results on the geometry and conformation of three compounds are reasonably consistent with those of X-ray and spectroscopic experiments as well as the previous calculations. The orientation of two carbonyl groups of malonyl methyl sulfide is quite similar to that of malonic acid, but different from that of its anion. Especially, the computed probable conformations of the sulfide anion by the three methods are different from each other. The role of hydration seems not to be crucial in stabilizing the overall conformations of malonic acid, hydrogen malonate, malonate, and malonyl methyl sulfide. However, the probable conformations of the unhydrated sulfide anion obtained by the MNDO and AM1 methods become less stabilized by including hydration. The AM1 method seems to be appropriate for conformational study of malonyl-CoA and its model compounds because it does not result in the formation of too strong hydrogen bonds and significant change in conformational energy from one compound to another.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.345-346
• /
• 2002

The electrical and rheological properties of a chitosan malonate suspension in silicone oil was investigated by varying the electric fields, volume fractions of particles, and shear rates, respectively. The chitosan malonate susepnsion showed a typical electrorheological (ER) response caused by the polarizability of an amide polar group and shear yield stress due to the formation of multiple chains upon application of an electric field. The shear stress for the suspension exhibited a linear dependence on the volume fraction and an electric field power of 1.88. On the basis of the results, the newly synthesized chitosan malonate suspension was found to be an anhydrous ER fluid.

• BMB Reports
• /
• v.30 no.2
• /
• pp.132-137
• /
• 1997

In order to compare molecular structure, malonate decarboxylases from Acinetobacter calcoaceticus, Pseudomonas fluorescens, and Pseudomonas putida aerobically grown on malonate, were purified by the method employing streptomycin sulfate treatment, chromatography with PBE 94 and ${\omega}-aminohexyl$ agarose. Molecular masses were estimated to be 185, 200, and 200 kDa, respectively. All malonate decarboxylases were multimeric enzymes consisting of four different subunits, $2{\alpha},\;1{\beta},\;1{\gamma},\;and\;1{\delta}$. The molecular masses of the Pseudomonas enzyme subunits were $65({\alpha})$, $33({\beta})$, $30({\gamma})$, and $11kDa({\delta})$; which are very similar to those, $65({\alpha})$, $32({\beta})$, $25({\gamma})$, and $11kDa({\delta})$ of Acinetobacter enzyme. The ${\delta}-subunit$ of the active form of the enzymes was acetylated. The acetyl group may form a thioester bond with the thiol group of the prosthetic group covalently linked to the enzyme. It suggests that such molecular organization is common in all malonate decarboxylases.

• Journal of the Korean Chemical Society
• /
• v.51 no.5
• /
• pp.403-406
• /
• 2007

• Journal of the Korean Chemical Society
• /
• v.44 no.1
• /
• pp.30-36
• /
• 2000

Upon Pd(0)-catalyzed coupling reaction of (2R)-2-(N,N-ditosylimido)-3-butenyl methyl malonate (4) which was selected for the total synthesis of A-factor, (3R)-2-(6-methylheptanoyl)-3-hydroxy methyl-4-buttinolide (1), an unexpected 14-membered cyclic compound, bis(2-methoxycabonyl-(4E)-hexenolide) (15) was obtained. The structure of this compound was conformed by X-ray crystallography. This result implies that this method can be applied the synthesis of various size of symmetrical macrocyclic compounds.

• Toxicological Research
• /
• v.9 no.2
• /
• pp.167-175
• /
• 1993

Protective effects of dithiol malonate derivatives (DMDs), YH-100, YH-150 and YH-439 on carbon tetrachloride-induced hepatotoxicity were investigated in primary rat hepatocytes culture. Treatment of DMDs to hepatocytes culture did not affect total cytochrome P-450 content and ECOD and AHH activities. Protein and RNA synthesis was also similar to control. Meanwhile, DMDs significantly decreased LDH release and in vitro lipid peroxidation induced by $CCI_4$. Accumulation of cellular triglyceride and decreased secretion of VLDL from liver cells by $CCI_4$ treatment were also significantly protected.

• Journal of the Korean Chemical Society
• /
• v.29 no.5
• /
• pp.539-542
• /
• 1985

Direct condensation of 3,4,5-trimethoxybenzoyl chloride with diethyl malonate followed by chlorination and hydrogenolysis afforded diethyl 3,4,5-trimethoxybenzylmalonate in 70% overall yield.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.10
• /
• pp.1631-1634
• /
• 2005

• Bulletin of the Korean Chemical Society
• /
• v.15 no.5
• /
• pp.394-399
• /
• 1994

The catalytic mechanism of malonyl-CoA synthetase from Rhizobium trifolii was investigated by the steady state kinetics and intermediate identification. Initial velocity studies and the product inhibition studies with AMP and PPi strongly suggested ordered Bi Uni Uni Bi Ping-Pong Ter Ter system as the most probable steady state kinetic mechanism of malonyl-CoA synthetase. Michaelis constants were $0.17{\pm}0.04 {\mu}M,\;0.24{\pm}0.18 {\mu}M\;and\;0.045{\pm}0.26 {\mu}$M for ATP, malonate and CoA, respectively. The TLC analysis of the $^{32}P-labelled$ products in reaction mixture containing $[{\gamma}-^{32}P]$ ATP in the absence of CoA showed that PPi was produced after the sequential addition of ATP and malonate. Formation of malonyl-AMP, suggested as an intermediate in the kinetically deduced mechanism, was confirmed by the analysis of $^{31}P-NMR$ spectra of AMP product isolated from the $^{18}O$ transfer experiment using $[^{18}O]$malonate. Two resonances were observed, corresponding to AMP labelled with zero and one atom of $^{18}O$, indicating that one atom of $^{18}O$ transferred from $[^{18}O]$malonate to AMP through the formation of malonyl-AMP. Formation of malonyl-AMP was also confirmed through the TLC analysis of reaction mixture containing $[{\alpha}-^{32}P]$ATP. These results strongly support the ordered Bi Uni Uni Bi Ping-Pong Ter Ter mechanism deduced from the initial velocity and product inhibition studies.

• Korean Journal of Metals and Materials
• /
• v.46 no.11
• /
• pp.725-729
• /
• 2008

Deposition characteristics of electroless plated Ni-W-P films were investigated for various complexing agents. Used complexing agents are sodium citrate, sodium gluconate and sodium malonate. In this study, the existing mixed potential theory could explain the overall mechanism of Ni-W-P electroless plating for all complexing agents. The deposition rate could be also expected by the theory. The deposited Ni-W-P films were evaluated in term of surface hardness and corrosion resistance. Microhardness of the deposit increased about 1,000 Hv after heat treatment for one hour at $400^{\circ}C$, because it was above the crystallization temperature of $Ni_3P$. The deposited Ni-W-P films can exhibit excellent corrosion resistance in using sodium malonate as a complexing agent, the other hand the using sodium gluconate was the worst corrosion resistance. The worst corrosion resistance was due to a large number of nano-sized pin-holes or small pores. The plating current at the mixed potential increases when the using sodium malonate as a complexing agent, it was explained by the cross section.