• BMB Reports
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• 제28권2호
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• pp.107-111
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• 1995

In malonate grown Pseudomonas fluorescens, malonate decarboxylase and acetyl-CoA synthetase were induced, whereas in Acinetobacter calcoaceticus malonate decarboxylase, acetate kinase, and phosphate acetyltransferase were induced. In both bacteria malonate decarboxylase was the first, key enzyme catalyzing the decarboxylation of malonate to acetate, and it was localized in the periplasmic space. Acetate thus formed was metabolized to acetyl-CoA directly by acetyl-CoA synthetase in Pseudomonas, and to acetyl-CoA via acetyl phosphate by acetate kinase and phosphate acetyltransferase in Acinetobacter.

• 약학회지
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• 제6권1호
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• pp.25-27
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• 1962

The derivative of glycyrrhetinic acid which have similar effects of desoxycorticosterone acetate was prepared glycyrrhetinyl chloride by the chlorination with thionyl chloride at low temperature. 2-Acetyl-11-keto-.DELTA. : 13 oleanolic ketol acetate (30) was synthesized by diazotating glycyrrhetinyl chloride with diazomethan and the acetylation with anhydro acetic acid. 2-Acetyl-.DELTA.12 : 13 oleanolic ketol acetate (28) was synthesized by chlorinating oleanolic acid with thionyl chloride, and by diazotatating oleanolyl chloride with diazomethan and the acetylation with anhydroacetic acid.

• BMB Reports
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• 제40권5호
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• pp.708-714
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• 2007

The two-component signal transduction, which typically consists of a histidine kinase and a response regulator, is used by bacterial cells to sense changes in their environment. Previously, the SphS-SphR histidine kinase and response regulator pair of phosphate sensing signal transduction has been identified in Synechocystis sp. PCC 6803. In addition, some response regulators in bacteria have been shown to be cross regulated by low molecular weight phosphorylated compounds in the absence of the cognate histidine kinase. The ability of an endogenous acetyl phosphate to phosphorylate the response regulator, SphR in the absence of the cognate histidine kinase, SphS was therefore tested in Synechocystis sp. PCC 6803. The mutant lacking functional SphS and acetate kinase showed no detectable alkaline phosphatase activity under phosphate-limiting growth conditions. The results suggested that the endogenous acetyl phosphate accumulated inside the mutants could not activate the SphR via phosphorylation. On the other hand, exogenous acetyl phosphate could allow the mutant lacking functional acetate kinase and phosphotransacetylase to grow under phosphate-limiting conditions suggesting the role of acetyl phosphate as an energy source. Reverse transcription PCR demonstrated that the transcripts of acetate kinase and phospho-transacetylase genes in Synechocystis sp. PCC 6803 is up-regulated in response to phosphate limitation suggesting the importance of these two enzymes for energy metabolism in Synechocystis cells

• 한국자원식물학회지
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• 제31권1호
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• pp.10-15
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• 2018

황칠나무 잎과 줄기를 분리하여 각각 methanol 추출하여, 계통분획상법에 따라 dichloromethane, ethyl acetate, butanol로 분획하였다. 분획물로 실시한 TLC에서 알칼로이드 성분으로 분리되는 성분을 확인할 수 있었다. 잎과 줄기 모두 ethyl acetate분획물은 $IC_{50}$ $30{\mu}g/m{\ell}$으로 높게 측정 되었으며, ethyl acetate, dichloromethane, butanol분획물 순으로 저해 활성이 높게 나타났다. Acetyl cholinesterase inhibition assay를 실시한 결과 황칠나무 잎과 줄기 모두 dichloromethane, ethyl acetate, butanol 분획물 순으로 저해 활성이 높은 것으로 나타났으며, 가장 높은 활성을 보인 황칠나무 줄기와 잎의 dichloromethane 분획물의 알칼로이드 함량이 상대적으로 높은 것으로 보아 알칼로이드 성분에 의한 것으로 유추 할 수 있으므로, 알칼로이드 성분의 동정 및 성분구조의 규명을 통하여 AChE저해 활성을 이용한 신경관련 질환에 도움을 줄 수 있는 천연물의 개발이 가능할 것으로 사료된다.

• 생약학회지
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• 제18권1호
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• pp.50-53
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• 1987

Two triterpenes were isolated from the root of Agastache rugosa (Labiatae). Compound I, mp $238{\sim}240^{\circ}$, was identified as erythrodiol-3-O-acetate and Compound II, mp $223{\sim}225^{\circ}$, as 3-O-acetyl oleanolic aldehyde.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1127-1134
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• 2009

Escherichia coli excretes acetate during aerobic growth on glycolytic carbon sources, which has been explained as an overflow metabolism when the carbon flux into the cell exceeds the capacity of central metabolic pathways. Nonacetogenic growth of E. coli on gluconeogenic carbon sources like succinate or in carbon-limited slow growth conditions is believed an evidence for the explanation. However, we found that a strain defected in the acs (acetyl Co-A synthetase) gene, the product of which is involved in scavenging acetate, accumulated acetate even in succinate medium and in carbon-limited low growth rate condition, where as its isogenic parental strain did not. The acs promoter was inducible in noncatabolite repression condition, whereas the expression of the ackA-pta operon encoding acetate kinase and phosphotransacetylase for acetate synthesis was constitutive. Results in this study suggest that E. coli excretes and scavenges acetate simultaneously in the carbon-limited low growth condition and in nonacetogenic carbon source, and the activity of the acetate consumption pathway directly affects the accumulation level of acetate in the culture broth.

• Bulletin of the Korean Chemical Society
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• 제4권3호
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• pp.139-143
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• 1983

${\beta}$-N-Acetyl-D-glucosaminidase B was highly purified with the following sequence of steps; DEAE-cellulose, CM-cellulose, and Sephadex G-200 gel filtration chromatograpies. The specific activity of the purified ${\beta}$ -N-acetyl-D-glucosaminidase B was 2.2 units/mg protein with 12.9 % yield and 196.2 fold purity. The purified ${\beta}$-N-acetyl-D-glucosaminidase B showed single band on polyacrylamide gel electrophoresis. The final preparation of ${\beta}$ -N-acetyl-D-glucosaminidase B was completely free friom arylsulfatase and ${\beta}$-glucuronidase. ${\beta}$ -N-Acetyl-D-glucosaminidase B had pH optimum of 4.5 in 0.5 M sodium citrate buffer. The molecular weight of ${\beta}$-N-acetyl-D-glucosaminidase B was 133,000 by Sephadex G-200 gel filtration. The Km value of ${\beta}$-N-acetyl-D-glucosaminidase B using p-nitrophenyl-N-acetyl-${\beta}$-D-glucosaminide as substrate was 1.0 mM and $V_{max}$ was 0.014 ${\mu}$ mole/min. ${\beta}$-N-Acetyl-D-glucosaminidase B was stable at $55^{circ}C$ for 70 minutes. The crude ${\beta}$ -N-acetyl-D-glucosamiinidase in 70 % ammonium sulfate retained 93 % activity after 7 months storage at -$55^{circ}C$. Bovine serum albumin, sodium chloride, and phosphate activated ${\beta}$ -N-Acetyl-D-glucosaminidase B. N-Acetyl-D-glucosamine, ${\alpha}$-methyl-D-mannoside, and acetate inhibited ${\beta}$ -N-acetyl-D-glucosaminidase B.

• BMB Reports
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• 제29권4호
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• pp.277-285
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• 1996

In Pseudomonas fluorescens grown on malonate as sole carbon source, acetyl-CoA synthetase was induced, suggesting that malonate is metabolized through acetate and then acetyl-CoA. Acetyl-CoA synthetase was purified 18.6-fold in 4 steps to apparent homogeneity. The native molecular mass of the enzyme estimated by a native acrylamide gel electrophoresis was 130 kDa. The enzyme was composed of two identical subunits with a molecular mass of 67 kDa. Optimum pH was 70. The acetyl-CoA synthetase showed typical Michaelis-Menten kinetics for the substrates, acetate, ATP and CoA, whose $K_m$ values were calculated to be 33.4, 74.8, and 40.7 mM respectively. Propionate. butyrate and pentanoate were also used as substrates by the enzyme, but the rate of the formation of the CoA derivatives was decreased in the order of the increase in carbon number. The enzyme was inhibited by the group-specific reagents diethylpyro-carbonate, 2,3-butanedione, pyridoxal-5'-phosphate and N-bromosuccinimide. In the presence of substrates the inactivation rate of the enzyme, by all of the group-specific reagents mentioned above decreased, indicating the presence of catalytically essential histidine, arginine, lysine and tryptophan residues at or near the active site. Preincubation of the enzyme with ATP, $Mg^{2+}$ resulted in the increase of its susceptibility to diethylpyrocarbonate, suggesting that ATP, $Mg^{2+}$ may induce a conformational change in the active site exposing the essential histidine residue to diethylpyrocarbonate. The enzyme was acetylated in the presence of acetyl-CoA, indicating that this is one of acyl-enzyme.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.507-514
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• 1994

Acetyl xylan esterase was produced by E. coli HB101 harboring a recombinant plasmid pKMG6 which contained the estI gene of Bacillus stearothermophilus. The maximum production was observed when the E. coli strain was grown at 37$\circC for 12 hours in the medium containing 0.5% acetyl xylan, 1.0% tryptons, 1.0% sodium chloride, and 0.5% yeast extract. The esterase produced was purified to homogeneity using a combination of ammonium sulfate fractionation, DEAE Sepharose CL-6B ion exchange chromatography and Sephacryl S-200 gel filtration. The native enzyme had an apparent molecular mass of 60 kd and was composed of two identical subunits of 29 kd. The N-terminal amino acid sequence of the polypeptide was Ala-X-Leu-Gln- Ile-Gln-Phe-X-X-Gln. The acetyl esterase displayed a pH optimum of 6.5 and a temperature opti- mum of 45$\circC. The heavy metal ions such as Ag$^{++}$, Hg$^{++}$ and Cu$^{++}$ inhibited nearly completely the activity of the esterase, and no specific metal ion was found to be required for the enzyme activity. The enzyme readily cleaved MAS, $\beta$-D-glucose pentaacetate, $\alpha$-naphthyl acetate, $\rho$-nitrophenyl acetate as well as acetyl xylan, but had no activity on $\rho$-nitrophenyl propionate, $\beta$-nitrophenyl butyrate or $\beta$-nitrophenyl valerate. The Km and Vmax values for MAS were 2.87 mM and 11.55 $\mu$mole/min, respectively. Synergistic behavior was demonstrated with a combination of xylanase and esterase from B. stearothermophilus in hydrolyzing acetyl xylan.

• 식물병연구
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• 제15권2호
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• pp.112-119
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• 2009

Botrytis cinerea가 생산하는 phytotoxin이 병원성에 미치는 영향을 조사하던 중에 두 개의 새로운 phytotoxin을 발견하였다. 1994년과 1996년에 여러 식물체로부터 분리한 Botrytis cinerea 균주들을 기주별, 지역별, 형태적 특성별로 25개의 균주를 선별한 후 단포자 분리를 실시하였다. 22균주는 오이, 토마토, 고추 담배, 배추 등 5가지 식물에 대해 강하거나 중간 정도의 병원성을 보였다. 그러나 KJ 균주를 포함한 3균주는 병원성이 매우 약하였다. 식물에 대한 phytotoxicity를 조사하기 위하여 25균주의 배양 여액을 담배잎에 leaf-wounding assay를 실시한 결과 2-16균주가 가장 강한 활성을 보였다. 따라서 2-16 균주의 배양액을 ethyl acetate로 추출한 후 flash silica gel column chromatography, silica gel column chromatography, Sephadex LH-20 column chromatography, preparative TLC 및 preparative HPLC 등을 통하여 두 개의 phytotoxin을 분리하였다. 분리한 phytotoxin을 질량분석과 핵자기 공명분석을 통해 구조동정을 실시한 결과 3-O-acetyl botcinol과 3-O-acetyl botcinolide로 동정하였다. 두 개의 물질은 leaf-wounding bioassay에서 잎에 괴사를 일으켰으며, 또한 담배 잎에서 심각한 전해질 누출을 일으켰다. 두 생물검정에서 3-O-acetyl botcinol이 3-O-acetyl botcinolide보다 강한활성을보였다. B. cinerea가 생산한 두 개의 phytotoxin에 대해서는 본 논문에서 처음으로 보고하는 바이다.