• 제목/요약/키워드: barley $\alpha$-amylase 2

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Enzymatic Properties of Barley $\alpha$-Amylase Chimeric Enzymes Produced by Staggered Extension Process (Staggered Extension Process를 통해 제조한 보리 알파아밀라제 Chimera 효소의 특성)

  • Kim, Tae-Jip;Choi, Seung-Ho;Jang, Myoung-Uoon;Park, Jung-Mi;Svensson, Birte
    • Microbiology and Biotechnology Letters
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    • 제38권2호
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    • pp.151-157
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    • 2010
  • Barley malt produces two different $\alpha$-amylase isozymes (AMY1 and AMY2), which share up to 80% of amino acid sequence identity with each other. However, their enzymatic properties differ remarkably. In this study, five chimeric enzymes between AMY1 and 2 were constructed by staggered extension process (StEP) technique, and their enzymatic properties were characterized. According to the results, chimeric AMY-D2, D8, and E12 showed the mixed or intermediate types of calcium-dependent activity between AMY1 and 2. Meanwhile, only AMY-E10 chimera could be significantly inhibited by barley $\alpha$-amylase/subtilisin inhibitor (BASI) protein. Chimera AMY-C6 showed the same calcium-dependency as AMY1, while AMY-E10 was closely similar to AMY2. As a result, it can be proposed that some amino acid residues in the region II, III, and IV of barley $\alpha$-amylases can play very important roles in the interaction with BASI, and those in III, V, VI, and VII may partly affect on the calcium-dependent activity.

Characterization of Barley ${\alpha}$-Amylase Chimeric Enzymes Expressed in Pichia pastoris (Pichia pastoris에서 발현된 보리 알파아밀라제 Chimera 효소들의 특성)

  • Kim, Tae-Jip;Yuk, Jeong-Bin;Choi, Seung-Ho;Jang, Myoung-Uoon;Svensson, Birte
    • Korean Journal of Microbiology
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    • 제46권1호
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    • pp.80-85
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    • 2010
  • Two different ${\alpha}$-amylase isozymes (AMY1 and AMY2) found in barley malt share up to 80% of amino acid sequence identity with each other, but their enzymatic properties differ remarkably. AMY1 shows the highest activity at low concentration of calcium ion, while AMY2 is highly active at high calcium concentration. Meanwhile, BASI (Barley ${\alpha}$-Amylase/Subtilisin Inhibitor) protein specifically inhibits only AMY2. In the present study, three separate regions in AMY genes (I, II, and III) were assigned on the basis of restriction enzyme sites and four kinds of chimeric amylases have been obtained by swapping a part of regions with each other. Each chimera gene was successfully over-expressed in Pichia pastoris. From the results of enzymatic characterization, both AMY211 and AMY122 showed the mixed or intermediate type of calcium-dependent activity between AMY1 and 2. Meanwhile, only AMY221 chimera could be significantly inhibited by BASI protein. As a result, it can be proposed that some amino acid residues in the region I and II, except region III, of barley ${\alpha}$-amylases play very important roles in calcium-dependency and interaction with BASI.

Characteristics of Germinated Rice as a Potential Raw Material for Sikhe Production (식혜원료로의 활용가능성 검토를 위한 발아미의 특성 조사)

  • Kim, Suk-Shin;Lee, Won-Jong
    • Korean Journal of Food Science and Technology
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    • 제29권1호
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    • pp.101-106
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    • 1997
  • This study was carried out to examine the possibility of using brown rice or paddy as raw materials for sikhe. Brown rice and paddy were soaked in water at $15^{\circ}C$ for 2 days and then germinated at $15,\;20,\;25,\;30^{\circ}C$ for upto 10 days. The higher the germination temperature, the higher the germination speed, the increase of ${\alpha}-amylase$ activity, and the increase of extract amount and its sugar content. The viscosity of extract rapidly decreased first and then slightly increased during germination. The activities of ${\alpha}-amylase$ of germinated brown rice and paddy were much smaller than those of germinated barley; however, the extract amount and its sugar content of germinated brown rice and paddy were similar to those of germinated barley. The germinated brown rice can be used for sikhe not as a saccharifying agent but as a substitute for white rice.

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Studies on Gibberellic Acid-promoted and Indole-3-acetic Acid-repressed Amylase Synthesis of Barley Seeds (대맥종자의 Amylase 생성에 미치는 Gibberellic Acid의 촉진효과와 Indole-3-acetic Acid의 억제효과의 해석)

  • 채인기
    • Journal of Plant Biology
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    • 제20권2호
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    • pp.91-101
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    • 1977
  • Using barley seeds (Hordeum sativum Jess, var.), the influences of gibberellic acid (GA) and indole-3-acetic acid(IAA) on the amylase synthesis and that of the nucleic acid metabolism were investigated. 1. With the deembrynized barley seeds, the increase of amylase treated with a $10^{-5}M$ of GA and the decrease of amylase treated with $10^{-5}M$IAA were matched by a proportionate increase and decrease in the amount of RNA. The influence of the hormones on the RNA synthesis has appeared immediately after the treatment but on the amylase synthesis it has appeared 8 hours later. But no influence on the DNA synthesis was observed on both hormones. 2. The amylase from deembryonized barley seeds treated with GA and IAA have been fractionated by gel filteration on Sephadex G-100. The amylase components showed four fractions on both enzymes treated with GA and IAA. Fraction I(FI) was differed from fraction Ⅵ(FIV) in Km value and the effects of temperature, pH and metal ions. On the basis of their emzymatic properties, it was considered that the FI was $\beta$-amylase and FIV was $\alpha$-amylase. The influences of GA and IAA on each fractions appeared to be similar but on the amylase units per souble protein, IAA inhibited the production of amylase FIV while it promoted that of amylase FI. 3. An experiment was conducted to determine whether IAA inhibits GA-promoted amylase synthesis competitively or non-competitively. Using a Lineweaver-Burk plot, it was clear that IAA was acting in a non-competitive fashion. From this, IAA was probably not competing with GA at the same site, but it was acting at some other site which resutled in partial blocking of the action of GA on the amylase synthesis.

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Quality Characteristics of Nochies Saccharified by Amylases from Various Sources (효소원을 달리한 노치의 품질 변화)

  • 이종미;윤희정
    • Korean journal of food and cookery science
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    • 제12권4호
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    • pp.522-534
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    • 1996
  • The present study was conducted to investigate quality characteristics of Nochi made with malted barley flour with (Cl) and without hull (C2), comparing with Nochi that was treated with different sources of commercial amylases. There was higher level of moisture content (18.4%) in Nochi treated with fungal ${\alpha}$-amylase (FU) comparing with the other Nochi samples. However, Nochi that was treated with bacterial ${\alpha}$-amylase and ${\beta}$-amylase (BA-${\beta}$) had the lowest level of moisture content (11.2%). Nochi samples which were treated with thermostable ${\alpha}$-amylase and fungal ${\alpha}$-amylase(TE-FU) were different from traditional Nochi samples in mechanical characteristics. According to the results of sensory evaluation, Cl was similar to C2 except in cohesiveness and malt flavor. TE-FU and Bh-${\beta}$ were not different from traditional Nochi in cohesiveness, sweetness and overall desirability.

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The activity of ${\alpha}$-amylase and ${\alpha}$-glucosidase as anti-diabetic function

  • Kim, Misook;Kim, Eunji;Kwak, Han Sub;Jeong, Yoonhwa
    • Nutrition Research and Practice
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    • 제8권5호
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    • pp.602-606
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    • 2014
  • BACKGROUND/OBJECTIVES: We investigated total 26 ingredients of Saengshik which will be commercially produced as an anti-diabetic dietary supplement. SUBJECTS/METHODS: Thirteen vegetables, nine cereals, three legumes and one seed were extracted with aqueous ethanol for 2 h at $60^{\circ}C$, and evaluated for their inhibitory effects against ${\alpha}$-amylase and ${\alpha}$-glucosidase and for total phenolic and flavonoid contents. RESULTS: All ingredients inhibited ${\alpha}$-amylase activity except cabbage. Strong inhibitory activity of ${\alpha}$-amylase was observed in leek, black rice, angelica and barley compared with acarbose as a positive control. Stronger inhibition of ${\alpha}$-glucosidase activity was found in small water dropwort, radish leaves, sorghum and cabbage than acarbose. All Saengshik ingredients suppressed ${\alpha}$-glucosidase activity in the range of 0.3-60.5%. Most ingredients contained total phenols which were in the range of 1.2-229.4 mg gallic acid equivalent/g dried extract. But, total phenolic contents were not observed in carrot, pumpkin and radish. All ingredients contained flavonoid in the range of 11.6-380.7 mg catechin equivalent/g dried extract. CONCLUSIONS: Our results demonstrate that Saengshik containing these ingredients would be an effective dietary supplement for diabetes.

Effect of Hypoxia on Carbohydrate Metabolism in Barley Seedlings (저산소 조건이 보리 유묘의 탄수화물대사에 미치는 영향)

  • Choi Heh Ran;Park Myoung Ryoul;Kim Jung Gon;Namkoong Seung Bak;Choi Kyeong-Gu;Yun Song Joong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • 제50권3호
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    • pp.170-174
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    • 2005
  • Barley plants growing in the wet paddy field easily encounter suboptimal oxygen concentration in the rhizosphere that causes molecular oxygen deficiency in root cells. The capacity of root cells to utilize energy sources is known to be positively related to resistance to hypoxia stress. This study was conducted to investigate effects of hypoxia on enzymes involved in the starch and sucrose metabolism. Barley seedlings at the third leaf stage were subjected to hypoxia (1 ppm dissolved oxygen) by purging the culture solution with nitrogen gas for up to seven days. The protein content was slightly decreased by hypoxia for 7 days. $\alpha-Amylase$ activities increased significantly in the root but not in the shoot after 3 to 7 days of hypoxia. $\beta-Amylase$ activities were not affected significantly in both tissues. Additionally, sucrose synthase activities were affected little in both tissues by 7 days of hypoxia. The results indicate that root cells activate break­down of polysaccharide reserves in response to an acute hypoxia to supply energy sources for fermentative glycolysis and cell wall fortification.

Effects of Enzyme Treatments on Quality and Yields of Barley Tea (보리의 효소처리가 보리차의 품질 및 수율에 미치는 영향)

  • Kim, Woo-Jung;Ko, Hwan-Kyung;Yoon, Suk-Kwon
    • Korean Journal of Food Science and Technology
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    • 제21권4호
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    • pp.583-589
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    • 1989
  • In order to improve the quality and yields of barley tea(water extracts), enzymatic hydrolysis was carried out with using three kinds of mired enzymes of ${\alpha}-amylase,\;{\beta}-amylase$ and protease. The barley treated with enzymes were the crushed , soaked and slightly roasted(light brown) Youngsanbori(hulless) and the physical, chemical and sensory characteristics were investigated. The results showed that enzymatic hydrolysis caused a signigicant increase in solid yields (80%) of barley tea, particularly with the mixed enzyme 5,000 which has higher activity of ${\alpha}-amylase$ than the other enzymes. The intrinsic viscosity of barley tea was reduced by enzymatic hydrolysis as the value of dextrose equivalent increased The Hunter L, a, b values was lower for the enzyme treated barley tea but showed not significant difference with reaction time. The organoleptic evaluation clearly showed that both intensity and acceptability of odor and taste was markedly Increased. The roasted nutty, and sweety odor and taste were particular in increase by mixed enzyme 5,000.

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Enhanced Expression and Substrate Specificity Changes of Barley $\alpha$-Amylase Isozyme 2 in E. coli by Substitution of the $42^{nd}$ Alanine Residue with Proline (42번째 alanine 잔기의 proline 치환에 의한 보리 $\alpha$-amylase isozyme 2의 대장균 내 발현 증가 및 기질특이성 변화)

  • Choi, Seung-Ho;Jang, Myoung-Uoon;Lee, Hong-Gyun;Svensson, Birte;Kim, Tae-Jip
    • Korean Journal of Food Science and Technology
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    • 제42권2호
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    • pp.198-203
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    • 2010
  • Although barley $\alpha$-amylase isozyme 1 (AMY1) and 2 (AMY2) share up to 80% of amino acid sequence identity, their enzymatic properties differ remarkably. In this study, the 42nd alanine residue of AMY2 was replaced with another random amino acid via saturation mutagenesis. Eight out of 370 recombinant E. coli cells showing enhanced starch-hydrolyzing activity were characterized as possessing the same proline residue instead of alanine. Even though the specific activity of AMY2-A42P is reduced to 81% of wild-type, its expression level and purification yield were enhanced by approximately 2 and 4 times that of AMY2, respectively. Characterization of its enzymatic properties confirmed that AMY2-A42P is similar to that of wild-type. However, its specificity to starch substrates is likely to be intermediate between AMY1 and AMY2.

Effect of Anaerobic Treatment on Carbohydrate-Hydrolytic Enzyme Activities and Free Amino Acid Contents in Barley Malt

  • Yun, Song-Joong;Choi, Kyeong-Gu;Kim, Jin-Key
    • KOREAN JOURNAL OF CROP SCIENCE
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    • 제43권1호
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    • pp.19-22
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    • 1998
  • Effects of acute anoxia on carbohydrate hydrolytic enzyme activities and free amino acid contents in malt were examined. Malts were prepared with barley grains germinated for 7 days which contained the highest levels of amylolytic and(1-3,1-4)-$\beta$-glucanase activities. $\alpha$-Amylase and $\beta$-amylase activities in malts were not significantly affected by anoxia for 5 or 10 h.(1-3,1-4)-$\beta$-Glucanase activity, however, decreased about 7 to 10% by anoxia for 5 or 10 h. Alanine and $\gamma$-aminobutyric acid content changed drastically. Alanine contents in malts increased by 2.2- and 2-fold, and $\gamma$-aminobutyric acid contents by 1.4- and 1.9-fold under anoxia for 5 and 10 h, respectively.

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