• Molecules and Cells
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• 제45권7호
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• pp.495-501
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• 2022

Leucine dehydrogenase (LDH, EC 1.4.1.9) catalyzes the reversible deamination of branched-chain L-amino acids to their corresponding keto acids using NAD⁺ as a cofactor. LDH generally adopts an octameric structure with D4 symmetry, generating a molecular mass of approximately 400 kDa. Here, the crystal structure of the LDH from Pseudomonas aeruginosa (Pa-LDH) was determined at 2.5 Å resolution. Interestingly, the crystal structure shows that the enzyme exists as a dimer with C2 symmetry in a crystal lattice. The dimeric structure was also observed in solution using multiangle light scattering coupled with size-exclusion chromatography. The enzyme assay revealed that the specific activity was maximal at 60℃ and pH 8.5. The kinetic parameters for three different amino acid and the cofactor (NAD⁺) were determined. The crystal structure represents that the subunit has more compact structure than homologs' structure. In addition, the crystal structure along with sequence alignments indicates a set of non-conserved arginine residues which are important in stability. Subsequent mutation analysis for those residues revealed that the enzyme activity reduced to one third of the wild type. These results provide structural and biochemical insights for its future studies on its application for industrial purposes.

• 한국식품영양학회지
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• 제9권4호
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• pp.372-378
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• 1996

최소 배지에 여러 아미노산을 첨가하여 배양시킨 Serratia marcescens ATCC 25419 세포 추출물에서 threonine dehydratase의 비활성을 조사한 결과 이소루신은 1~4mM에서 효소의 비활성을 100~140% 정도 증가시킨 반면 15~30mM에서 25~80% 정도 감소시켰다. 루신은 효소의 비활성을 1~120mM에서 60% 이상 감소시켰다. 한편, 발린은 효소의 비활성을 1~4mM에서 20% 정도, 8~10mM에서 10% 정도 감소시켰으나 20mM에서 효소의 비활성을 원래대로 회복시켰다. 각 2mM 농도의 이소루신과 발린 그리고 이소루신과 루신은 효소의 비활성을 각각 75, 50%씩 증가시킨 반면 세 아미노산을 각각 2과 10mM씩 동시 첨가했을 경우에는 각각 25, 58%씩 감소시켰다. 글리옥실산은 효소의 비활성을 75%, 이마다졸, 피루브산, $\alpha$-아미노부티르산 그리고 AMP는 모두 50%씩, 호모세린, $\alpha$-케토글루타르산, $\alpha$-케토부티르산 및 IPTG를 첨가했을 경우는 모두 25%씩 감소시켰다. cAMP는 효소의 비활성을 1~2mM에서 10~40% 정도 감소시킨 반면 10mM에서 80% 증가시켰다. 이러한 결과들로부터 S. marcescens threonine dehydratase는 E. coli K-12 효소와는 다르게 낮은 농도의 이소루신에 의해 효소의 비활성이 증가되고, 높은 농도의 이소루신 (10~30mM)에 의해서는 감소되는 등 이소루신 생합성 과정에서 조절 역할을 하는 것으로 생각된다.

• Journal of Genetic Medicine
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• 제11권1호
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• pp.22-26
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• 2014

Maple syrup urine disease (MSUD) is a disorder that involves the metabolism of branched chain amino acids, arising from a defect in branched-chain ${\alpha}$-keto acid dehydrogenase complex. Mutations have been identified in the BCKDHA, BCKDHB, or DBT genes, which encode different subunits of the BCKDH complex. Although encephalopathy and progressive neurodegeneration are its major manifestations, the severity of the disease may range from the severe classic type to milder intermediate variants. We report two Korean siblings with the milder intermediate MSUD who were diagnosed with MSUD by a combination of newborn screening tests using tandem mass spectrometry and family genetic screening for MSUD. At diagnosis, the patients' plasma levels were elevated for leucine, isoleucine, valine, and alloisoleucine, and branched-chain ${\alpha}$-keto acids and branched-chain ${\alpha}$-hydroxy acids were detected in their urine. BCKDHA, BCKDHB, and DBT analysis was performed, and two novel mutations were identified in BCKDHB. Our patients were thought to have the milder intermediate variant of MSUD, rather than the classic form. Although MSUD is a typical metabolic disease with poor prognosis, better outcomes can be expected if early diagnosis and prompt management are provided, particularly for milder forms of the disease.

• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.295-306
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• 2007

The growth and health of the fetus and neonate are directly influenced by the nutritional and physiological status of sows. Sows are often under catabolic conditions due to restrict feeding program during pregnancy and low voluntary feed intake during lactation. The current restrict feeding program, which aims at controlling energy intake during gestation, results in an inadequate supply of dietary protein for fetal and mammary gland growth. Low voluntary feed intake during lactation also causes massive maternal tissue mobilization. Provision of amino acids and fatty acids with specific functions may enhance the performance of pregnant and lactating sows by modulating key metabolic pathways. These nutrients include arginine, branched-chain amino acids, glutamine, tryptophan, proline, conjugated linoleic acids, docosahexaenoic acid, and eicosapentaenoic acid, which can enhance conception rates, embryogenesis, blood flow, antioxidant activity, appetite, translation initiation for protein synthesis, immune cell proliferation, and intestinal development. The outcome is to improve sow reproductive performance as well as fetal and neonatal growth and health. Dietary supplementation with functional amino acids and fatty acids holds great promise in optimizing nutrition, health, and production performance of sows and piglets. (Supported by funds from Texas Tech, USDA, NLRI-RDA-Korea, and China NSF).

• 한국잡초학회지
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• 제16권2호
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• pp.122-131
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• 1996

옥수수 잎으로부터 추출한 ALS를 대상으로 하여 CHL과 IMA의 상호작용, ALS의 기질인 pyruvate 및 2-ketobutyrate에 대한 친화도, 저해양식의 차이 등을 조사한 결과는 다음과 같다. 1. ALS 에 대한 CHL의 $I_{50}$값은 100nM이었으며 IMA의 값은 $5{\mu}M$로 나타나 CHL의 ALS 저해활성은 IMA보다 약 50배 정도 높았다. 2. ALS에 대한 시험관내에서의 실험에서 두 제초제의 동시처리시 상가적인 ALS의 저해효과가 나타났으나, 상호 순차적 체계처리의 경우에서는 먼저 처리한 제초제에 의한 저해효과가 지배적으로 나타났다. 3. 제초제에 의한 ALS 활성의 저해는 시험관내에서 10분 이내에 대부분 이루어졌다. 4. ALS의 활성은 분지아미노산에 의해 저해되었는데 Val과 Leu에 의한 저해가 Ile에 의한 저해보다 크게 나타났다. 또한 이들을 동시에 혼합처리하면 0.1mM의 농도에서도 ALS의 활성이 65% 정도 저하되었다. 5. 2-Ketobutyrate를 ALS의 기질로 첨가하면 pyruvate만을 기질로 사용하였을 때보다 측정가능한 ALS 활성이 2-ketobutyrate에 의해 농도의존적으로 감소되는 경향이었다. 6. ALS의 기질인 pyruvate에 대해 CH은 비경쟁적 저해제로 IMA는 반경쟁적 저해제로 작용하였다.

• BMB Reports
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• 제32권2호
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• pp.210-213
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• 1999

In Serratia marcescens, acetolactate produced by the catabolic acetolactate synthase (ALS) is converted into acetoin, its physiological role of which is to maintain intracellular pH homeostasis. In this study, the expression mode of catabolic ALS by aeration and branched-chain amino acids was examined by the ELISA method. The amount of catabolic ALS decreased approximately 93% under aerobic conditions. We also showed that the expression of catabolic ALS decreased approximately 34 % and 65 % in the presence of 2.5 mM and 10 mM leucine, respectively. The repression of catabolic ALS by leucine has not been reported previously. In contrast to leucine, catabolic ALS levels increased approximately 13% and 38% by treatment with 2.5 mM and 10 mM isoleucine, respectively, while valine alone did not have any significant effect on the synthesis of catabolic ALS. The amount of catabolic ALS was also reduced to approximately 32% and 45% in the presence of 10 mM Leu+Ile and Leu+Ile+Val, respectively. The regulatory mode of the Serratia catabolic ALS suggests that catabolic ALS may also have a role in supplying acetolactate as an intermediate of valine and leucine biosynthesis in addition to the maintenance of internal pH.

• 한국산학기술학회논문지
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• 제20권8호
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• pp.523-530
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• 2019

본 연구는 고 탄수화물식품인 설기떡에 단백질함량이 높은 탈지 밀웜 분말 첨가량(0, 3, 6, 9 및 12%)을 달리하여 제조한 설기떡의 품질특성으로 색도, 기계적 물성, 관능평가, 일반성분, 분지사슬 아미노산 함량을 평가하였다. 품질 특성 평가를 수행한 결과, 색도의 경우 명도(L) 값은 탈지 밀웜 분말 첨가비율이 증가할수록 유의하게 낮아진 반면, 적색도(a)과 황색도(b) 값은 탈지 밀웜 분말 첨가비율이 증가할수록 유의하게 높아졌다. 탈지 밀웜 분말 첨가량에 따른 설기떡의 기계적 물성 측정결과 경도, 검성은 탈지 밀웜 분말 첨가비율이 증가할수록 유의하게 높아진 반면, 씹힘성, 탄력성과 응집성에서는 유의하게 낮아졌다. 탈지 밀웜 분말 첨가량에 따른 설기떡의 관능평가의 경우, 탈지 밀웜 분말을 6% 첨가한 설기떡(MS-6)의 색, 맛, 향 및 전반적인 기호도 점수가 가장 높았다. 탈지 밀웜 분말을 6 % 첨가한 설기떡(MS-6)의 일반성분을 대조군과 비교한 결과, 대조군과 MS-6간에 수분함량과 조회분 함량에는 차이가 없었으나, 단백질 함량은 MS-6이 높았고 탄수화물은 대조군이 높았다. 탈지 밀웜 분말을 6 % 첨가한 설기떡(MS-6)의 분지사슬 아미노산(BCAA) 함량을 대조군과 비교한 결과, 대조군에 비해 탈지 밀웜 분말 첨가로 근육형성 기능을 하는 branched amino acids인 valine($275.8{\pm}3.41mg/100g$), leucine($414.3{\pm}5.87mg/100g$) 및 isoleucine($188.9{\pm}2.31mg/100g$)의 함량이 유의적으로 증가되었다. 이상의 결과 탈지 밀웜 분말을 6 % 첨가한 설기떡(MS-6)은 일반성분 중 단백질함량, 아미노산 중 분지사슬 아미노산(valine, leucine 및 isoleucine) 함량이 대조군에 비해 높아져 영양적 단점이 보완되어 단백질 강화식품으로의 활용가치가 높을 것으로 보여진다.

• 한국식품영양과학회지
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• 제13권4호
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• pp.451-458
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• 1984

18% casein식(食)을 대조식이(對照食餌)로 하여 분지쇄(分枝?) 아미노산(Leu. lie. Val.)을 첨가(添加)한 실험식이(實驗食餌)의 간부분절제후(肝部分切除後)의 Rat에 대한 영양학적(營養學約) 효과(效果)를 검토(檢討)하였다. 자유채취(自由攝取)시키면, 실험식이군(寶驗食餌群)은 대조식이군(對照食餌群)에 비하여 6일(日)째까지 식이채취량(食餌攝取量)이 적지만, 8 일(日)째부터는 증가하고 체중증가(體重增加)도 그와 평행하였다. 14 일(日)째에 간(肝)의 부분절제(部分切除)를 행하면, 7 일후의 체중(體重)은 식이채취량(食餌攝取量)은 동일(同一)하면서도 실험식이군(實驗食餌群)에서 유의(有意)하게 증가(增加)하였다. 또한 간부분절제후(肝部分切除後) 5 일(日)째의 간재생중량(肝再生重量) 및 간재생지수(肝再生指數)도 유의(有意)하게 증가(增加)를 나타내었다. 이상으로 보아, 분지쇄(分枝?)아미노산 첨가식이(添加食餌)는 재생간(再生肝) Rat에 대하여 체중증가(體重增加) 및 간재생(肝再生) 보호작용(促進作用)에 있어서 영양학적(營養學論) 효과(效果)가 있다는 것이 인정(認定)된다.

• 농약과학회지
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• 제2권3호
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• pp.1-20
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• 1998

Chlorsulfuron, one of sulfonylurea herbicides acts through inhibition of acetolactate syuthase (EC 4.1.3.18; ALS, also known as acetohydroxyacid synthase) in the branched-chain amino acid biosynthesis process. After chlorsulfuron-ALS interaction, many physiological and metabolic disruptions occur in plants. However, it is not clear how this chlorsulfuron-ALS interaction affects those physiological and metabolic processes and how this interaction leads subsequently to plant death. Several researchers suggested that the death of chlorsulfuron-treated plants might be due to a shortage of the branched-chain amino acids, an accumulation of toxic metabolites, and/or a depletion of photoassimilates. It remains as a mystery presently, however, if such changes result in the plant death. In this review, we discussed how the chlorsulfuran-ALS interaction leads to physiological and metabolic disruptions in plants.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4074-4078
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• 2012

The first step in the common pathway for the biosynthesis of branched chain amino acids is catalyzed by acetohydroxyacid synthase (AHAS). The AHAS is found in plants, fungi and bacteria. With an aim to identify new anti-tuberculosis drugs that inhibit branched chain amino acid biosynthesis, we screened a chemical library against Mycobacterium tuberculosis AHAS. The screening identified four compounds, AVS 2087, AVS 2093, AVS 2236, and AVS 2387 with $IC_{50}$ values of 0.28, 0.21, 3.88, and $0.25{\mu}M$, respectively. Moreover, these four compounds also showed strong inhibition against reconstituted AHAS with $IC_{50}$ values of 0.37, 0.26, 1.0, and $1.18{\mu}M$, respectively. The basic scaffold of the AVS group consists of 1-pyrimidin-2-yl-1H-[1,2,4]-triazole-3-sulfonamide. The most active compound, AVS 2387, showed the lowest total interaction energy -8.75 Kcal/mol and illustrates its binding mode by hydrogen bonding with $H_{\varepsilon}$ of Gln517 with the distance of $2.24{\AA}$.