• Journal of Nutrition and Health
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• 제27권9호
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• pp.892-900
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• 1994

A variety of important roles for branched-chain amino acids in metabolic regulation has been suggested. Branched-chain $\alpha$-keto acid dehydrogenase(BCKAD) complex is a rate limiting enzyme in branched-chain amino acid metabolism. The purpose of this study was to examine the effects of exercise on the activity and activity state of branched-chain $\alpha$-keto acid dehydrogenase in rat hert and liver thssues. Forty-eight Sprague-Dawley rats were assigned into three experimental groups : sedentary control, exercised, or exercised-rested. Submaximal exercise(running) for two hours significantly increased basal activity without a change in total activity in both tissues, with a concomitiant increase in activity state of the enzyme complex. At 10 min post-exercise, heart enzyme activity significantly decreased, though not to the control level, while liver enzyme activity remained unchanged. These data suggested that the exercise-induced increase in branched-chain $\alpha$-keto acid decarboxylation in rat tissues may not be the result of enzyme synthesis, but rather is due to increased activity of the BCKAD.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.115-121
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• 1992

최소 배지에 여러가지 아미노산들을 첨가하여 배양한 Serratia marcescens ATCC 25419 세포 추출물에서 acetolactate syhthase(ALS)의 비활성도를 0.5mM에서 40 증가시킨 반면 8mM에서 60, 20mM에서 90 감소시켰다. Valine은 효소의 비활성도를 2-4 mM에서 20-40 정도 증가시켰고 20mM의 높은 농도에서 10 정도 감소시켰다.

• 대한유전성대사질환학회지
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• 제3권1호
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• pp.4-14
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• 2003

Maple syrup urine disease or branched chain ketoacidurias caused by a deficiency in activity of the branched-chain ${\alpha}$-keto acid dehydrogenase(BCKD) complex. This metabolic block results in the accumulation of the branched-chain amino acids(BCAAs) leucine, isoleucine and valine, and the corresponding branched chain ${\alpha}$-keto acids (BCKAs). Based on the clinical presentation and biochemical responses to thiamine administration, MSUD patients can be divided into five phenotypes : classic, intermediate, intermittent, thiamine responsive and dihydrolipoyl dehydrogenase(E3)-deficient. Classic MSUD has a neonatal onset of encephalopathy, and is the most severe ad most common form. Variant forms of MSUD generally have the initial symptoms by 2 years of age. The majority of untreated classic patients die within the early months of life from recurrent metabolic crisis and neurologic deterioration. Treatment involves both longterm dietary management and aggressive intervention during acute metabolic decompensation. We report here our experience of longterm diet therapy and treatment of acute metabolic decompensation of a case of classic MSUD.

• Parasites, Hosts and Diseases
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• 제21권1호
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• pp.49-57
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• 1983

The distribution and Properties of branched chain amino acid aminotransferase (EC 2.6. 1.42) was investigated in adult Fasciola hepatica. Fascicla hepatica was fractionated by differential centrifugation into nuclear, mitochondrial and cytosolic fractions. The activity of branched chain amino acid aminotransferase was measured by the method of Ichihara and Koyama (1966) . Isozyme patterns of this enzyule was also examined by DEAE-cellulose column chromatography. The results obtained were as follows; 1. The activity in homogenate was found to be 12.69 units/g wet tissue. The activity of this enzyme was relatively high compared with those in rat tissues. 2. The distribution of branched chain amino acid aminotransferase in the subcellular organelles showed that 87.8% of the activity was in cytosolic, 10.9% in mitochondrial and 1.3% was in nuclear fraction. 3. Cytosolic fraction of Fasciola hepatica contained Enzyme I, but not Enzyme II and III, of branched chain amino acid aminotransferase. Ensyme I was eluted by 50mM phosphate buffier from DEAE-cellulose column and catalyzed the transamination of all three branched chain amino acids. 4. The Enzyme I was purified about 22-folds increase in specific activity after chromatography on DEAE-cellulose. 5. The best substrate among three amino acids (leucine, isoleucine and valise) was L-isoleucine. 6. The optimal temperature of Enzyme I was $45^{\circ}C$ and the optimal pH was 8.2. 7. The Km value for leucine of Enzyme I was 4.17 mM. 8. The Km values for a-ketoglutarate and pyridoxal phosphate of Enzyme I were 0.41mM and $4.76{\times}10^{-3}{\;}mM$, respectively.

• Journal of Plant Biotechnology
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• 제48권4호
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• pp.228-235
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• 2021

The amino acids found in plants play important roles in protein biosynthesis, signaling processes, and stress responses, and as components in other biosynthesis pathways. Amino acid degradation helps maintain plant cells' energy states under certain carbon starvation conditions. Branched-chain amino acid transferases (BCATs) play an essential role in the metabolism of branched-chain amino acids (BCAAs) such as isoleucine, leucine and valine. In this paper, we performed genome-wide RNA-seq analysis using CsBCAT7-overexpressing Arabidopsis plants. We observed significant changes in genes related to flowering time and genes that are germination-responsive in transgenic plants. RNA-seq and RT-qPCR analyses revealed that the expression levels of some BCAA catabolic genes were upregulated in these same transgenic plants, and that this correlated with a delay in their senescence phenotype when the plants were placed in extended darkness conditions. These results suggest a connection between BCAT and the genes implicated in BCAA catabolism.

• BMB Reports
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• 제28권1호
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• pp.12-16
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• 1995

The branched-chain ${\alpha}$-keto acid dehydrogenase (BCKAD) complex is a rate limiting enzyme which catalyzes the oxidative decarboxylation of branched-chain ${\alpha}$-keto acids. Numerous studies have suggested that BCKAD is subject to covalent modification in vitro via phosphorylation and dephosphorylation, which are catalyzed by a specific kinase and phosphatase, respectively. The biggest difficulty in the assay of BCKAD activity is to arrest the interconversion between the active and inactive forms. BCKAD activity was determined from fresh rat heart and liver tissues using homogenizing and assay buffers containing inhibitors of phosphatase and kinase. The results suggest that a radiochemical assay using ${\alpha}$-keto[1-$^{14}C$]-isovalerate as a substrate for the enzyme can be applied as a reliable method to determine in vitro enzyme activity with arrested interconversion between the active and inactive forms of the BCKAD complex.

• 한국잡초학회지
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• 제17권2호
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• pp.199-206
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• 1997

Acetolactate synthase를 저해하는 sulfonylurea계 제초제 chlorsulfuron은 감수성 식물 체내에서 많은 생리, 생화학적 변화를 유도한다. 이 연구의 목적은 chlorsulfuron이 유발하는 독성이 감수성 식물체내에서 branched-chain 아미노산 생합성경로의 최종산물인 leucine, valine과 isoleucine의 결핍에 의한 것인지 혹은 branchedchain 아미노산 생합성 경로중 독성 대사산물의 축적에 의한 것인지를 결정하는 것이다. Chlorsulfuron에 처리된 캐놀라의 성장은 저해되었으며, 처리된 식물은 백화 현상, 잎말이 현상 그리고 안토시아닌 축적과 같은 약해증상을 보였다. Branched-chain 아미노산이 첨가된 영양배양액에서 생장하는 캐놀라에 chlorsulfuron을 처리하였을 경우 생장저해와 약해는 단지 부분적으로 완화되었다. 이와 같은 사실은 chlorsulfuron에 처리된 캐놀라의 약해는 branched-chain 아미노산의 결핍 이외에 또 다른 요인이 있음을 시사하는 것이다. 독성 대사산물로 알려진 2-ketobutyrate에 처리된 캐놀라 식물체내에서의 대사산물 변화와 chlorsulfuron에 처리된 캐놀라 식물체내에서의 대사산물 변화는 서로 다른 양상을 보였다. 본 연구에서 얻어진 결과들은 chlorsulfuron에 처리된 감수성 식물이 나타내는 독성은 부분적으로 branched-chain 아미노산의 결핍에 의한 것이라는 점을 시사한다.

• 한국식품영양과학회지
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• 제22권3호
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• pp.300-306
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• 1993

2-Methylbutanoic, 3-methylbutanoic, 4-methylpentanoic, 2-ethylhexanoic, 4-methylhexanoic, 4-methyloctanoic, 6-methyloctanoic, 4-ethylhexanoic. 4-methylhexanoic 및 2-ethylhexanoic acids를 포함하는 다수의 volatile branched-chain fatty acids(VBCFAs)가 쇠고기, 돼지고기, 염소고기(미국산 흰염소고기, 한국산 흑염소고기), 양고기로부터 분리, 동정되었다. 쇠고기 향은 amino acid, carbohydrate, 그리고 lipid의 반응에 의해 생성된 향기성분에 의해 이루어지는 기본 meaty flavor로 결정되어 지는 반면, 염소고기가 양고기의 경우는 쇠고기의 기본향에 4-ethyloctanoic acid와 4-methyloctanoic acid의 독특한 노린내가 더해지므로 염소고기나 양고기 특유의 향을 내었다. 돼지고기는 3-methylbutanoic acid 함량이 다른 세종류에 비해 높고 3-methylbutanoic acid 특유의 꼬린냄새는 돼지고기의 기름층으로부터 나는 unclean flavor 에 중요한 영향을 미치는 것으로 생각된다. 염소고기는 C5-C7 chain length의 volatile branched 및 n-chain fatty acids를 적게 함유하고 있는 반면 4-ethyloctanoc acid는 염소고기의 노린내를 내는 결정적인 화합물이었다. 4-Methyloctanoic acid는 양고기의 sweaty-muttony flavor를 내는 중요한 화합물이었으며 염소고기와는 달리 C5, C6, 그리고 C7 branched-chain fatty acids 도 상당량 함유되어 있었다. 한국산 흑염소고기와 미국산 흰염소고기 중에 들어있는 VBCFAs의 종류는 같으나, 한국산 흑염소고기가 미국산 흰염소고기 보다 노린내가 강하며 4-ethyloctanoic 의 함량도 높았다.

• Korea-Australia Rheology Journal
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• 제19권1호
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• pp.1-5
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• 2007

By combining ultrasonic energy which is essential for the chain scission of polymer molecules and a multifunctional agent (MFA) having double bonds at its ends, we were able to modify the molecular structure of polycarbonate (PC) from linear to a branched structure during melt processing. The three double bonds in chain ends of MFA were expected to act as sites for trapping macroradicals of PC during the course of ultrasound-assisted mixing process. The transformation of molecular structure of PC was confirmed by the measurements of rheological properties of the modified PC. After the ultrasonic irradiation of PC together with MFA, increase in complex viscosities and shear-thinning behavior were observed. The Cole-Cole plot and measurement of extensional viscosities revealed the characteristic features of branched structure with well-defined extensional behavior which is comparable to that of a commercial branched PC.

• 대한임상검사과학회지
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• 제37권2호
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• pp.78-83
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• 2005

The optimum conditions of Cordyceps militaris mycelial growth, purification and characteristics of branched-chain amino acid aminotransferase [BCAT(EC 2.6.1.42)] in this mycelium were studied. Optimum pH, temperature and medium of culture of mycelia were 5.5, $22.5^{\circ}C$ and Hamada medium (HM), respectively. BCAT in homogenate of this mycelia was precipitated by 20-40% saturated solution of ammonium sulfate and then purified by DEAE (diethylaminoethyl)-Sephadex A-50 column chromatography with linear concentration gradient and Sephadex G-200 gel filtration. A single band of purified enzyme was detected on SDS-PAGE (sodium dodecylsulfate-polyacrylamide gel electrophoresis). Optimum pH and temperature of BCAT were found to be 7.8 and $29^{\circ}C$, respectively. It showed activity toward L-leucine, L-isoleucine and L-valine as a substrate. The Km values of this enzyme for L-leucine were determined to be 5.88 mM for L-leucine.