• Applied Biological Chemistry
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• v.38 no.5
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• pp.473-477
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• 1995

The dichloromethane extracts of the above ground parts of Hymenoxys brachyactis afforded three sesquiterpene lactones already reported, one new sesquiterpene lactone, biennin C and hispidulin as known toxic flavone. Structures of all compounds were established by spectroscopy and biennin C was determined as an adduct of the modified pseudoguanolide and hymenoxon by Gas Chromatograpy and MS spectrometer These sesquiterpene lactones have the same ${\alpha},{\beta}$-unsaturated functional group like that of hymenovin which has been known as major toxic constituent of important livestock poison. And biennin C is also considered as toxic compound because of toxic hymenoxon.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.64-64
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• 1995

Cholesteryl Ester Transfer Protein (CETP) mediates the transfer of cholesterol ester and triglyceride between high-density lipoprotein (HDL) and other low-density lipoproteins, therefore, it might influence HDL levels. The levels of HDL is closely related to the atherogenic diseases in human and there were several reports that the trasgenic mice expressing CETP had much worse atherosclerosis than non-expressing control one. Therefore, selective inhibitors of CETP have the potential to be used as antiatherosclerotic agents. Continued screening for potent inhibitors of CETP led to the isolation of Suberitenone B from marine sponge. Suberitenone B, sesterterpenoids of a new skeletal class have been isolated from the sponge Suberites sp. collected from King George Island the Antartic. The structure of the metabolite has been determined by NMR experiments and chemical methods.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2002.10a
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• pp.8-8
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• 2002

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.53-53
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• 2005

• BMB Reports
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• v.30 no.1
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• pp.13-17
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• 1997

The inhibitory effect of herbicides such as sulfonylurea derivatives, imidazolinones and pyrimidylsalicylate has been examined on the purified valine sensitive acetolactate synthase (ALS) from Serratia marcescens. The concentration of sulfometuron methyl which inhibits 50% of the ALS activity was 2.5 mM. The required concentrations of triasulfuron, primisulfuron methyl and imazaquin for the 50% inhibition of the ALS activity were 1 mM. The resistance of Serratia ALS to sulfometuron methyl, imazapyr and imazaquin is similar to that of E. coli ALS 1. However, pyrimidylsalicylate showed a potent inhibitory effect on the Serratia ALS almost 13 times more potent than on E. coli ALS II, which is known as herbicide-sensitive isozyme. The inhibitory mode was competitive against pyruvate. 150 value was determined to be $17{\mu}M$ in an assay mixture containing 20 mM pyruvate, and the $K_1$, value was calculated to be $0.4{\mu}m$ from the modified double reciprocal plot of 1/V versus $1/S^2$.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.96-99
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• 1995

Addition of l00mM $MgSO_4$ to a cell culture after 54 hours resulted in a 2.4-fold increase in the sisomicin titre compared to a control to which no $MgSO_4$ was added, and a considerable amount of intracellular sisomicin was liberated outside the cells. The occurrence of product inhibition in fermentation was confirmed by a reduction in net sisomicin production with increasing amounts of added sisomicin without addition of $MgSO_4$. All added sisomicin was bound to sisomicin-free cells in the absence of $MgSO_4$, whereas approximately 40% of added sisomicin was bound with the addition of l00mM $MgSO_4$. Under conditions of no enzmye synthesis, maintained by adding chloramphenicol to exclude product repression, sisomicin was produced in the presence of 100 mM $MgSO_4$ but little sisomicin was produced in the absence of $MgSO_4$.

• Journal of Microbiology and Biotechnology
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• v.5 no.2
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• pp.92-95
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• 1995

Halophilic Pseudomonas sp.W7 isolated from laver in the southem sea of Korea showed alginate lyase activity. Gene (aly) encoding alginate lyase was cloned in E.coli JM83 and the N-terminal amino acid sequence of the enzyme was determined after purificaion. The recombinant enzyme has been shown to have a molecular weight of about 40kDa after 12% SDS-polyacrylamide gel electrophoresis.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.338-342
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• 1994

The bacterium producing EPA was isolated from the intestines of the marine fishes. The strains were studied for their identification and their culture conditions. The selected strain was gram negative, rod(0.7 $\times$ 2.4 $\mu m$ in size) and motile with a single polar flagellum. This strain was identified as a Pseudomonas sp. on the basis of its morphological, cultural and physiological characteristics. The strain showed a maximum productivity of phospholipid at $20^{\circ}C$ after 48 hours of culture time with an initia1 pH of 7.0 in the PYM-glucose medium. Under these culture conditions, the production of phospholipid was about 0.3 mg/ml and 0.06 mg/mg dry cell weight.

• BMB Reports
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• v.30 no.4
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• pp.246-252
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• 1997

Malonate decarboxylase from Acinetobacter calcoaceticus is shown to have malonyl-CoA: acetate CoA transferase. acetyl-CoA: malonate CoA transferase, and malonyl-CoA decarboxylase activity. These enzyme activities were elucidated by isotope exchange reactions. The enzyme modified by N-ethylmaleimide completely lost its malonate decarboxylase activity, whereas it still kept CoA transferases and malonyl-CoA decarboxylase activities. The existence of CoA transferases and malonyl-CoA decarboxylase activity is clear, but their physiological significance is obscure. The catalytic reactions for two eoA transfers and malonyl-CoA decarboxylation proceed via a cyclic mechanism, which is through two covalent intermediates, enzyme-Smalonyl and enzyme-S-acetyL proposed for malonate decarboxylation of the enzyme.

• BMB Reports
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• v.31 no.1
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• pp.37-43
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• 1998

The catabolic ${\alpha}$-acetolactate synthase was purified to homogeneity from Serratia marcescens ATCC 25419 using ammonium sulfate fractionation, DEAE-Sepharose, Phenyl-Sepharose, and Hydroxylapatite column chromatography. The native molecular weight of the enzyme was approximately 150 kDa and composed of two identical subunits with molecular weights of 64 kDa each. The N-terminal amino acid sequence of the enzyme was determined to be Ala-Gln-Glu-Lys-Thr-Gly-Asn-Asp-Trp-Gln-His-Gly-Ala-Asp-Leu-Val-Val-Lys-Asn-Leu. It was not inhibited by the branched chain amino acids and sulfometuron methyl herbicide. The optimum pH of the enzyme was around pH 5.5 and the pI value was 6.1. The catabolic ${\alpha}$-acetolactate synthase showed weak immunological relationships with recombinant tobacco ALS, barley ALS, and the valine-sensitive ALS isozyme from Serratia marcescens.