• 한국미생물·생명공학회지
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• 제23권5호
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• pp.573-579
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• 1995

A Bacillus strain capable of producing an extracellular malto-oligosaccharides forming $\alpha $-amylase was isolated from soil and designated as Bacillus sp. SUH4-2. The enzyme was purified by ammonium sulfate fractionation, DEAE-Toyopearl and Mono-Q HR 5/5 column chromatographies using a FPLC system. The specific activity of the enzyme was increased by 16.1-fold and the yield was 13.5%. The optimum temperature for the activity of $\alpha $-amylase was 60-65$\circ$C and more than 50% of initial activity was retained after the enzyme was incubated at 60$\circ$C for 40 min. The enzyme was stable over a broad pH range of 5.0-8.0 and the optimum pH was 5.0-6.0. The molecular weight of the enzyme was determined to be about 63.6 kD and isoelectric point was around 5.8. The enzyme activity was strongly inhibited by Mn$^{2+}$, Ni$^{2+}$, and Cu$^{2+}$ ; slightly by Ca$^{2+}$. The purified enzyme produced starch hydrolyzates containing mainly maltose and maltotriose from soluble starch. The starch hydrolyzates were composed of 11% glucose, 59% maltose, 25% maltotriose and 5% maltotetraose.

• 한국작물학회지
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• 제44권2호
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• pp.138-142
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• 1999

An experiment was carried out to find out the changes in morphology, sugars, and $\alpha$-amylase activity during the priming of rice seeds (Oryza sativa L. cv. ＇Ilpumbyeo＇). For priming, seeds were soaked in -0.6 MPa PEG solution at 15$^{\circ}C$ for 4 days (properly primed) and at $25^{\circ}C$ for 4 and 10 days (over-primed) and dried at room temperature. The size of coleoptile and differentiated leaves of properly primed seeds were bigger and coleoptile was separated from the other part of embryo compared with non-primed and over-primed seeds. As priming of seeds advanced, compound starch grains in the endosperm disintegrated into tiny starch granules, and small holes were found in the tiny starch granules and a cavities developed between embryo and endosperm. The radicle and plumule of properly primed germinating seeds developed faster than non-primed and overprimed germinating seeds. Sucrose, maltose, and raffinose contents of properly primed seeds decreased, while content of glucose and fructose and $\alpha$-amylase activity increased. However, sugar content and $\alpha$-amylase activity of over-primed seeds were lower compared with non-primed seeds or properly primed seeds.

• 한국조리학회지
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• 제23권1호
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• pp.95-102
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• 2017

This study was activity of ${\alpha}-amylase$, glucoamylase of liquid Nuruk prepared using liquid Nuruk (NK) and Aspergillus kawachii (AK), Aspergillus niger (AN), Aspergillus oryzae (AO), Monascus kaoliang (MK). To investigate the relationship between the enzymatic activity and the total sugar content of liquid Nuruk depending on the types of Nuruk molds and the degree of rice-polishing. The activity of ${\alpha}-amylase$ depending on the types of Nuruk molds was shown to be 8.82, 8.72 units/mL in AN and AK treatments in brown rice liquid Nuruk at 24 hours after incubation, as the degree of rice-polishing increased, the activity of ${\alpha}-amylase$ was significantly lower (p<0.05). When brown rice was incubated in AN, it showed 8.83 units/mL at 48 hours after incubation, which was the highest activity, but there was no significantly difference (p<0.05), as the degree of rice- polishing was higher, the activity of ${\alpha}-amylase$ was lower. The activity of glucoamylase depending on the degree of rice-polishing showed 3,013 units/mL in AO treatment in brown rice liquid Nuruk at 24 hours after incubation, and the enzymatic activity was significantly higher (p<0.05). As the degree of rice-polishing increased, the activity of glucoamylase decreased, so liquid brown rice Nuruk showed the highest enzymatic activity, liquid white rice Nuruk was the lowest enzymatic activity. The highest enzymatic activity appeared in liquid Nuruk with brown rice at 48 hours after incubation. The activity of ${\alpha}-amylase$, glucoamylase showed higher enzymatic productivity as the degree of rice-polishing was lower, and there was an inverse correlation with the total sugar content.

• 한국식품과학회지
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• 제26권4호
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• pp.398-402
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• 1994

잣죽의 점도를 낮추는 주요원인이 amylase작용에 의한 것임을 증명하기 위하여 잣으로부터 조효소를 분리하고 작용특성을 조사하였다. 잣의 초산완충액 추출물에 ammonium sulfate를 가하여 $35{\sim}55%$ 포화되도록 하였을 때 침전하는 획분이 가장높은 ${\alpha}-amylase$의 specific activity를 나타내었다. 이 효소의 적정 작용조건은 $75^{\circ}C$, pH5.4이었으며 쌀가루에 첨가하여 amylograph 양상을 관찰한 결과 쌀가루의 점도를 크게 낮추는 것으로 나타났다.

• 한국식품과학회지
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• 제5권4호
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• pp.224-230
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• 1973

The culture used wheat bran as media for four kind of mold strains such as Aspergillus oryzae, Aspergillus kawachii, Aspergillus usamii and Rhizopus javanicus to examine which strain could higher the activity of amylase most which is used for alcohol fermentation. It also provided three different kind of wheat bran media containing starch of 47%, 51% and 55% respectively for each strain. For each media it also added three different kind of nitrogen sources; ammonium sulfate, casein, and ammonium sulfate and casein equally mixed. Each nitrogen source added was subordinately differentiated into three different percentages, 2%, 4% and 6% respectively, except the 2% for the ammonium sulfate. The results obtained were summarized as follows (1) The activity of ${\alpha}-amylase$ was highest in the media of starch value 47% of wheat bran with 6% of casein added. (2) The activity of ${\beta}-amylase$ was highest in the media of starch value 51% of wheat bran with 2% of the equal mixture of ammonium sulfate and casein added. (3) The activities of both ${\alpha}-amylase$ and ${\beta}-amylase$ of Aspergillus usamii were highest in the media of starch value 47% wheat bran with no addition of nitrogen source. (4) Of the four strains examined, the activities of ${\alpha}-amylase$ and ${\beta}-amylase$ cultured in Rhizopus javanicus were both relatively higher. (5) The activities of ${\alpha}-amylase$ and ${\beta}-amylase$ of the strains examined became lower as the percentage of starch contents increased except in Rhizopus javanicus.

• Journal of Applied Biological Chemistry
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• 제59권1호
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• pp.75-81
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• 2016

Glutaraldehyde was used as a cross-linking agent for immobilization of purified ${\alpha}$-amylase from Exiguobacterium sp. DAU5. Befitting concentration of glutaradehyde and cross-linking time is the key to preparation of cross-linking chitosan beads. Based on optimized immobilization condition for ${\alpha}$-amylase, an overall yield of 56% with specific activity of 2,240 U/g on chitosan beads and 58% with specific activity of 2,320 U/g on chitosan-carbon beads was obtained. The optimal temperature and pH of each immobilized enzyme activity were $50^{\circ}C$ and 50 mM glycine-NaOH buffer pH 8.5, respectively. Those retained more than 75 and 90% of its maximal enzyme activity at pH 7.0-9.5 and after incubation at $50^{\circ}C$ for 1 h, respectively. In addition, the immobilization product showed higher organic-solvent tolerance than free enzymes. The mode of hydrolyzing soluble starch revealed that the ${\alpha}$-amylase possessed high hydrolyzing activity. These results indicate that chitosan is good support and has broad application prospects of enzyme immobilization.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.190-195
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• 1992

Polythylene glycol/dextran 수성 2단계에서 polyethylene glycol의분자량과 농도가 증가할수록 체적비는 증가하고 분배계수는 감소하였다. 또한 dextran의 분자량이 증가할 수록 체적비는 감소하고 분배계수는 증가하였다. 한편 dextran의 농도가 증가할수록 체적비와 분배계수는 감소하였다.

• Applied Biological Chemistry
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• 제42권4호
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• pp.324-329
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• 1999

엿기름의 적정 제조조건을 설정하기 위하여 발아조건를 달리하여 제조한 엿기름의 ${\beta}-glucanase$, ${\alpha}-amylase$ 및 ${\beta}-amylase$의 활성을 조사하였다. 보리는 발아가 진행됨에 따라 ${\beta}-glucanase$의 활성이 증가하였으며, 이로 인해 세포벽의 주요 구성다당류인 ${\beta}-glucan$이 분해되어 감소하였다. ${\beta}-Glucanase$ 활성은 $15^{\circ}C$의 발아온도에 비해 $18^{\circ}C$와 $21^{\circ}C$에서 발아초기에 급격히 증가하였으며 발아 6일경에는 최고값에 달하였다. 6조보리인 올보리의 ${\beta}-glucanase$ 활성이 2조보리인 진양보리에 비해 높게 나타났다. 올보리의 ${\alpha}-amylase$ 활성 역시 진양보리에 비해 현저히 높았으며 6일간의 발아일수에서 증가하는 경향이 있었다. 발아보리의 ${\alpha}-amylase$ 활성은 발아온도 $15^{\circ}C$에서 가장 낮았고 $18^{\circ}C$에서 가장 높았으며 $21^{\circ}C$에서는 약간 감소하였다. ${\beta}-Amylase$는 원맥에서 상당한 활성이 있었으며 발아과정중에 지속적으로 증가하는 경향을 보였다. $15^{\circ}C$에 비해 $18^{\circ}C$와 $21^{\circ}C$에서 발아일수에 따른 ${\beta}-amylase$ 활성의 증가폭이 컸으며 발아 5일 이후부터는 효소활성도에 있어서 크게 변화를 보이지 않았다. 엿기름의 당화력(diastatic power)은 올보리가 진양보리에 비해 $1.4{\sim}1.9$배 정도 높았으며 $18^{\circ}C$에서 $5{\sim}6$일의 발아가 당화력이 가장 우수한 것으로 나타나 발아조건으로서 적합한 것으로 제시되었다.

• Applied Biological Chemistry
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• 제21권2호
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• pp.103-108
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• 1978

Paecilomyces subglobosum이 생산하는 내산성 ${\alpha}-amylase$를 Sephadex G-150으로 정제한 결과 순수정제가 되지 않았으나 glucoamylase와 분리되었다. 조효소를 사용하여 내산성 amylase의 일반 성질을 조사한 결과 최적 pH는 4.0이었고 최적온도는 $38^{\circ}C$이었다. 이 효소는 보통 ${\alpha}-amylase$와 비교하여 pH에 대한 안정성은 매우 좋았으나 열 안정성은 비슷하였다. 전분에 대한 가수분해력이 좋았으며 생성물을 박충 크로마토그라피로 조사한 결과 말토스도 분해하는 것을 알았다.

• 한국식품영양과학회지
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• 제27권3호
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• pp.367-375
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• 1998

The physicochemical properties of the $\alpha$-amylase inhibitors from black bean and naked barley is Korea were investigated. Preincubation time for maximum inhibition was 30min and no activity change was seen after that time. Optimum pH of the $\alpha$-amylase inhibitors from the black bean and naked barley was pH 7.0 and the inhibitory activities were stable in the range of pH 6.0~8.0 in both phosphate and Tris-HCI buffer solutions. Both inhibitors maintained more than 50% of activity after incubation for 17 min at 7$0^{\circ}C$. The inhibitors from the black bean and naked barley maintained more than 50% of activities after treatment for 40 min and 30 min with pepsin, and 30 min and 50 min with trypsin, respectively. Both inhibitors functioned via a noncompetitive mechanism and were active against porcine pancreatic and human salivary $\alpha$-amylases. The activities of both inhibitors were linear for the ionic stength ranging from 0 to 0.9. The addition of 70 mM maltose to the reaction mixture caused a maximum increase in the relative activities of both inhibitors, but it did not affect the dissociation of the EI complex. The activities of both inhibitors were significantly enhanced by adding 1mM of K+ or Mg2+.