• Title, Summary, Keyword: imidazolinone

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Inhibition of Barley Acetolactate Synthase by Triazolopyrimidine Derivative (트리아졸로피리미딘계 유도체에 의한 보리 Acetolactate Synthase의 저해)

  • Kim, Sung Ho;NamGoong, Sung Keon;Shin, Jung Hyu;Chang, Soo Ik;Choi, Jung Do
    • Journal of the Korean Chemical Society
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    • v.43 no.4
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    • pp.461-468
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    • 1999
  • Acetolactate synthase (ALS) catalyzes the first common reaction in the biosynthesis of branched-chain amino acids, valine, leucine, and isoleucine. ALS is the common target of several classes of structurally diverse herbicides, the triazolopyrimidines, the imidazolinones, the sulfonylureas, and pyrimidyl-oxy-benzoates. We examined ihibitory activities of newly synthesized triazolopyrimidine sulfonamide derivatives using partially purified ALS from barley. $IC_{50}$ values for the active derivatives are 0.5nM∼8$\mu$M. Among them TP1 and TP2 are the most potent ALS inhibitors with $IC_{50}$ values of 0.5nM and 1.6nM, respectively. These inhibitors are more potent in the inhibition of barley ALS than commercial herbicides, Metosulam ($IC_{50}$;3.6 nM), Flumetsulam ($IC_{50}$;126 nM), and Cadre ($IC_{50};4 {\mu}M$). The progress curves for inhibition of ALS by TP2 showed that the amount of inhibition increases with time. The inhibition of ALS by TP2 was mixed-type inhibition with respect to pyruvate. Dual inhibition analyses of TP2 versus an imidazolinone, Cadre, and Leu showed parallel and intercepting kinetic pattern, respectively. The results suggest that TP2 binds to ALS competively with Cadre but not with Leu. Chemical modification of cysteinly residues in ALS decreased the sensitivity of ALS to Leu, while the modification did not affect the sensitivity of ALS to TP2 and Cadre.

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Interaction of Barley Acetolactate Synthase with Triazolopyrimidine Inhibitors (Triazolopyrimidine계 저해제와 보리 Acetolactate Synthase와의 상호작용)

  • Lee, Jae Soeb;Chang, Soo Ik;Nam Goong, Sung Keon;Shin, Jung Hyu;Choi, Jung Do
    • Journal of the Korean Chemical Society
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    • v.42 no.3
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    • pp.306-314
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    • 1998
  • Acetolactate synthase (ALS) is the common enzyme in the biosynthesis of branched chain amino acids, Val, Leu, and Ile in bacteria, yeast, and higher plants. The enzyme is target site of several classes of structually diverse herbicides, including the sulfonylureas, the imidazolinones, the triazolopyrimidines, and the primidyl-oxy-benzoates. We have synthesized new triazolopyrimidine (TP) derivatives, and determined their inhibitory activities on barley ALS. $lC_{50}$ values for the active compounds were 3.2 nM-0.62 mM, and some of them appeared to be potent inhibitors. The progress curves for inhibition of ALS by TP4, a representative derivative, indicated that the extent of inhibition increased with incubation time. The inhibition of ALS by TP4 showed mixed-type inhibition with respect to pyruvate. Dual inhibition analyses of TP4 versus imidazolinone Cadre and feedback inhibitor Leu suggested that three different classes of inhibitors bind to ALS in a mutually exclusive manner. Chemical modification of tyrosyl residues of ALS decreased sensitivity of ALS to TP4, while modification of tryptophan and cysteine did not affect the sensitivity.

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Synthesis of new pyridylimidazolinones and their hubicidal effects (새로운 Pyridylimidazolinone 유도체의 합성과 제초활성)

  • Jeon, Dong-Ju;Chang, Hae-Sung;Hwang, In-Taek;Kim, Dae-Whang
    • The Korean Journal of Pesticide Science
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    • v.3 no.3
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    • pp.6-10
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    • 1999
  • New series of pyridylimidazolinorus substituted with N-(2-hydroxyethyl)-${\alpha}$-dicarbonylamide group, N-ethoxycarbonylthioamide and N-benzoylthioamide group in place of carboxyl group at 3-position of pyridine were prepared, and their herbicidal effects were tested(in vivo) in upland conditions. Most of pyridylimidazolinones substituted with hydroxydiketoamide and N-ethoxycarbonylthioamide group at 3-position of pyridine showed good herbicidal effects at a rate of 250 g/ha, while pyridylimidazolinone substituted with N-benzoylthioamide group showed no herbicidal effects.

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Acetolactate Synthase Activity Inhibition and Herbicidal Activity of Sulfonylurea and Imidazolinone Herbicides (Sulfonylurea 및 imidazolinone계 제초제(除草劑)의 살초작용(殺草作用)과 acetolactate synthase 활성(活性) 억제작용(抑制作用))

  • Hwang, I.T.;Hong, K.S.;Cho, K.Y.
    • Korean Journal of Weed Science
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    • v.15 no.1
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    • pp.54-62
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    • 1995
  • Acetolactate synthase activity inhibition and herbicidal activities were investigated with 2 sulfonylureas [chlorsulfuron{2-chloro-N-{{(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino} carboxyl} benzenesulfonamide}, metsulfuron-methyl{methyl-2{{{{(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino}carbonyl}amino}sulfonyl}benzoic acid}, and 2 imidazoli-nones [imazethapyr{2-{4,5-dihydro-4-methyl-4-(1-methyl)-5-oxo-1H-imidazol-2-yl}-5-ethyl-3-pyridinecarboxylicacid}, imazaquin{2-{4,5-dihydro-4-methyl-4-(1-methyl)-5-oxo-1H-imidazol-2-yl}-3-quinoline carboxylic acid} herbicides. A broad weeding spectrum was observed with the treated herbicides at low application rates. Both corn(Zea mays L.) and sorghum(Sorghum bicolor Moench) were very sensitive to the two herbicide groups. Although legumes, such as soybean(Glycine max Merr.), clover(Trifolium repense L.), and indian jointvetch(Aeschnomene indica L.) were sensitive to the sulfonylureas, they were tolerant to the imidazolinones. On the contrary, wheat(Triticum aestivum L.) and barley(Hoderum sativum Jess.) showed the reverse responses of the legumes to the two herbicide groups. Quackgrass(Agropyron repens(L.) P. Beauv.). however, was commonly tolerant to the two herbicide groups. Degrees of crop injury and acetolactate synthase inhibition also varied with the crops examined. The 50% inhibition concentrations of sulfonylureas on acetolactate synthase in vitro activity($IC_{50}$) from corn, wheat, and soybean did not relate to the greenhouse herbicidal activities ($GI_{50}$). With chlorsulfuron, for example, wheat had more than 100 times higher $GI_{50}$ than corn and soybean, but the $IC_{50}$ was 4 to 10 times lower. Similar observation was made with metsulfuron-methyl. However, closer relationships between $IC_{50}$ and $GI_{50}$ were found with the imidazolinones. When imazethapyr was applied, the order of $GI_{50}$ values against com, wheat, and soybean was the same as that of $IC_{50}$.

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Separation and Characterization of Two Forms of Acetolactate Synthase from Etiolated Pea Seedlings

  • Shin, Yong-Soo;Chong, Chom-Kyu;Choi, Jung-Do
    • BMB Reports
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    • v.32 no.4
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    • pp.393-398
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    • 1999
  • Acetolactate synthase (ALS) catalyzes the first reaction common to the biosynthesis of L-valine, L-leucine, and L-isoleucine. ALS is the target site of several classes of herbicides, including the sulfonylureas, the imidazolinones, and the triazolopyrimidines. Two forms of ALS (ALS I and ALS II) which have different affinity for Heparin have been separated from etiolated pea seedlings. The substrate saturation curves of both ALS I and ALS II were hyperbolic in contrast to previous reports. The two forms of ALS showed significant differences in their physical and kinetic properties. The values of $K_m$ for ALS I and ALS II were 9.0 mM and 4.8 mM, respectively. The pI values for ALS I and ALS II were determined to be 5.3 and 5.75 by isoelectric focusing, respectively. The native molecular weights for ALS I and ALS II obtained by nondenaturing gel electrophoresis and activity staining were 124 and 244 kDa, respectively. They also exhibited different sensitivity to feedback inhibition by end-product amino acids and inhibition by Cadre, an imidazolinone herbicide.

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Wrinkle Recovery Properties of Cellulose Fabrics Treated with DMDHI and Silicone-Urethane Copolymer (실리콘-우레탄 공중합체와 DMDHI 처리된 셀룰로스 직물의 구김회복 특성)

  • 김선미;황택성;박진원;강윤욱;조인식;이승구
    • Textile Science and Engineering
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    • v.41 no.2
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    • pp.100-105
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    • 2004
  • To improve the crease resistance, we studied the effects of silicone-urethane copolymer coating on cellulose fabrics, such as those on the crease resistance, bursting strength, tensile strength, and water absorbency. With increase in the concentration of silicone-urethane copolymer, wrinkle recovery increased but other properties of fabrics such as bursting strength, tensile strength and water absorbency decreased. Wrinkle recovery of fabrics increased by the treatment with DMDHI (dimethyl dihydroxy imidazolinone) resin and silicone-urethane copolymer, and the maximum value was obtained with 20 wt% DMDHI resin, 6 wt% catalyst and 3 wt% silicone-urethane copolymer, respectively. The water absorbency value of fabrics treated with resin was similar to that of untreated, but decreased considerably by the addition of silicone-urethane copolymer. The surface of fabrics treated with resin and additive were observed on a image analyzer. The surface hairiness was reduced and the alignment of fibers in the fabric became uniform and the fabric became dense by resin and additive treatment.

Microbial degradation and other methods for accelerated degradation the Herbicide Imazapyr (제초제 Imazapyr 의 미생물에 의한 분해 및 기타 방법에 의한 분해 촉진)

  • Lee, Jae-Koo;Kwon, Jeong-Wook
    • Korean Journal of Environmental Agriculture
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    • v.17 no.1
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    • pp.5-10
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    • 1998
  • The microbial degradation, photosensitizer-mediated photolysis, and bioceramic- accelerated degradation of the herbicide imazapyr were investigated using four types of soil. 1. Seven strains of microorganisms isolated from the soil A and the active sludge collected from the waste water disposal plant in CheongJu did not give any distinct degradation products in pure culture. When imazapyr (10ppm) was incubated for 14days with each of the 6strains of the known bacteria, they did not produce any noticeable products, either, suggesting that imazapyr was degraded very little by microorganisms in aqueous media. Meanwhile, when 50ppm of imazapyr was incubated in soil A and B for 6months, a degradation product of m/z 279 was detected. It turned out to be 2-[(1-carbamoyl-1,2-dimethylpropyl)carbamoyl]nicotinic acid, which was formed by the hydrolytic cleavage of the imidazolinone ring and by tautomerism. When imazapyr was exposed to sunlight, degradation rates were 14.6% under the control and 66.0, 76.5, 26.7, and 90.0% in the presence of PS-1 (100ppm), PS-1 (200ppm), PS-2(100ppm), and PS-3(100ppm), respectively, and a degradation product of m/z 149 was tentatively identified in the treatment of PS-1. 2. When soil C and D treated with bioceramic were incubated for 7weeks, the $^{14}C$-activities of $^{14}CO_2$ evolved were 2.03 and 1.12% of the originally applied ones, respectively, whereas those in control soils without bioceramic were 1.88 and 0.82% showing no significant defferences.After 5 weeks, however,the differences in the amounts of $^{14}CO_2$ between the two treatments increased gradually, suggesting the bioceramic effect.

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Characterization of Two Forms of Acetolactate Synthase from Barley

  • Yoon, Jong-Mo;Yoon, Moon-Young;Kim, Young-Tae;Choi, Jung-Do
    • BMB Reports
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    • v.36 no.5
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    • pp.456-461
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    • 2003
  • Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of valine, leucine, and isoleucine. ALS is the target site for several classes of herbicides, including sulfonylureas, imidazolinones, and triazolopyrimidines. Two forms of ALS (designated ALS I and ALS II) were separated from barley shoots by heparin affinity column chromatography. The molecular masses of native ALS I and ALS II were determined to be 248 kDa and 238 kDa by nondenaturing gel electrophoresis and activity staining. Similar molecular masses of two forms of ALS were confirmed by a Western blot analysis. SDS-PAGE and Western blot analysis showed that the molecular masses of the ALS I and ALS II subunits were identical - 65 kDa. The two ALS forms exhibited different properties with respect to the values of $K_m$, pI and optimum pH, and sensitivity to inhibition by herbicides sulfonylurea and imidazolinone as well as to the feedback regulation by the end-product amino acids Val, Leu, and Ile. These results, therefore, suggest that the two ALS forms are not different polymeric forms of the same enzyme, but isozymes.

The Catalytic Role of the W573 in the Mobile Loop of Recombinant Acetohydroxyacid Synthase from Tobacco

  • Karim, Masud;Shim, Mi-Young;Kim, Jeong-Mok;Choe, Gyeong-Jae;Kim, Jung-Rim;Choi, Jung-Do;Yoon, Moon-Young
    • Bulletin of the Korean Chemical Society
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    • v.27 no.4
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    • pp.549-555
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    • 2006
  • Acetohydroxyacid synthase (AHAS, EC 2.2.1.6 also referred to as acetolactate synthase) catalyzes the first common step in the metabolic pathway leading to biosynthesis of the branched-chain amino acids in plants and microorganisms. Due to its presence in plants, AHAS is a target for the herbicides (sulfonylurea and imidazolinone), which act as potent inhibitors of the enzyme. Recently, we have shown [J. Kim, D.G. Baek, Y.T. Kim, J.D. Choi, M.Y. Yoon, Biochem. J. (2004) 384, 59-68] that the residues in the “mobile loop” 567-582 on the C-termini are involved in the binding/stabilization of the active dimer and ThDP (thiamin diphosphate) binding. In this study, we have demonstrated the role of the W573 in the mobile loop of the C-termini of tobacco AHAS. The substitution of this W573 residue caused significant perturbations in the activation process and in the binding site of ThDP. Position W573 plays a structurally important role in the binding of FAD, maintaining the enzyme active site in the required geometry for catalysis to occur. In here we propose that the tryptophan at position 573 is important for the catalytic process.

Purification and Characterization of Acetolactate Synthase from Barley

  • Chong, Chom-Kyu;Chang, Soo-Ik;Choi, Jung-Do
    • BMB Reports
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    • v.30 no.4
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    • pp.274-279
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    • 1997
  • Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of branchedchain amino acids, valine, leucine, and isoleucine. ALS is the target site for several structually diverse classes of herbicides including sulfonylureas, imidazolinones. and triazolopyrimidines. We have purified ALS from etiolated barley shoots to homogeneity. The five major purification steps are ammonium sulfate fractionation, DEAE anion exchange, hydroxylapatite, Bio-Gel A gel filtration, and low pressure Mono-Q chrornatoqraphy. Approximately 170-fold purification was achieved and the yield was 0.45% of initial activity in the crude extract. Both SDS-PAGE and Western blot analysis showed a single polypeptide of ALS with an apparent molecular mass of 64 kDa. The result of nondenaturing gel electrophoresis with activity staining indicated that the molecular mass of its native form is approximately 225 to 250 kDa. The values of $K_m$ for pyruvate. pl. and optimum pH of ALS were determined to be 2.0 mM, 5.2. and 7.0. respectively Feedback inhibition studies showed that ALS is more susceptible to leucine than valine. And $IC_{50}$ value of Cadre, a class of irnidazolinones, is about $1.5\mu{M}$ for ALS.

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