• 한국균학회지
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• 제17권3호
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• pp.149-153
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• 1989

내산성 ${\alpha}$-아밀라제를 강력히 생산하는 Aspergillus niger K-25 균주를 토양으로부터 분리하였다. 내산성 아밀라제 효소를 생산하기 위한 균주의 배양조건을 조사하였다. 합성배지 A(soluble starch 3.5%, peptone 2%, $KH_2PO_4$ 0.5%, $MaSO_4{\cdot}7H_2O$ 0.25%, $FeCI_3$ 1.0%, pH 6)에서 배양시 아밀라제 생산이 높았다. 밀기울에 fumaric acid 완충용액(pH3)을 1 : 1(W/V)로 첨가하여 배양했을 때 내산성 ${\alpha}$-아밀라제의 생산력은 완충액 HCI, citric acid과 밀기울만 넣은 배지보다 약 2배가 높았고, 배지 A보다 현저하게 높았다.

• 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.

• 한국균학회지
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• 제17권3호
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• pp.145-148
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• 1989

Aspergillus niger K-25가 생산하는 내산성 ${\alpha}-amylase$를 정제하여 특성을 조사하였다. 분자량은 전기영동상에서 약 58,000달톤으로 나타났고, 최적 pH는 4였고, pH3에서 활성을 잃어 버리는 시판효소와 달리 본 효소는 91%의 활성을 유지했다. 최적 온도는 $40^{\circ}C$였으며, $60^{\circ}C$에서도 80%의 활성을 유지하여 열에 대한 안정성도 높은 것으로 나타났다.

• 미생물학회지
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• 제10권3호
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• pp.106-108
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• 1972

The enzyme was produced by Asp.oryzae SHW 131. the enzymatic properties of .alpha.-amylase are following : 1) Crystallization of .alpha.-amylase is formed of longish square. 2) The range of stable pH is 5-10 and optimum ph is 5.5. 3) It is very unstable enzyme about EDTA and protection by $Ca^{++}$ ion and best activated at $50^{\circ}C$ about temperature. 4) Asp.oryzae SHW 131 produced .alpha.-amylase with acid-protease, neutral-protease and tepid-alkalin-protease.

• 미생물학회지
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• 제10권3호
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• pp.105-105
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• 1972

The enzyme was produced by Asp.oryzae SHW 131. the enzymatic properties of .alpha.-amylase are following : 1) Crystallization of .alpha.-amylase is formed of longish square. 2) The range of stable pH is 5-10 and optimum ph is 5.5. 3) It is very unstable enzyme about EDTA and protection by $Ca^{++}$ ion and best activated at $50^{\circ}C$ about temperature. 4) Asp.oryzae SHW 131 produced .alpha.-amylase with acid-protease, neutral-protease and tepid-alkalin-protease.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 1991년도 춘계학술발표대회 논문집
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• pp.225-236
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• 1991

The genes encoding the thermostable $\alpha$-amylase and maltogenic amylase from Bacillus lichenciformis were cloned and expressed in E. coli. The recombinant plasmid pTA322 was found to contain a 3.1kb EcoRI genomic DNA fragment of the thermostable $\alpha$-amylase. The cloned $\alpha$-amylase was compared with the B. licheniformis native $\alpha$-amylase. Both $\alpha$-amylase have the same optimal temperature of $70^{\circ}C$ and are stable in the pH range of 6 and 9. The complete nucleotide sequences of the thermostable $\alpha$-amylase gene were determined. It was composed of one open reading rame of 1,536 bp. Start and stop codons are ATG and TAG. From the amino acid sequence deduced from the nucleotide sequence, the cloned thermostable $\alpha$-amylase is composed of 483 amino acid residues and its molecular weight is 55,200 daltons. The content of guanine and cytosine is $47.46mol\%$ and that of third base codon was $53_41mol\%$. The recombinant plasmid, pIJ322 encoding the maltogenic amylase contains a 3.5kb EcoRI-BamHI genomic DNA fragment. The optimal reaction temperature and pH of the maltogenci amylase were $50^{\circ}C$ and 7, respectively. The maltogenic amylase was capable of hydrolysing pullulan, starch and cyclodextrin to produce maltose from starch and panose from pullulan. The maltogenic amylase also showed the transferring activity. The maltogenic amylase gene is composed of one open reading frame of 1,734bp. Start and stop codons are ATG and ATG. At 2bp upstream from start codon, the nucleotide sequence AAAGGGGGAA seems to be the ribosome-binding site(RBS, Shine-Dalgarno sequence). A putative promoter(-35 and-10 regions) was found to be GTTAACA and TGATAAT. From deduced amino acid sequence from the nucleotide srquence, this enzyme was comosed of 578 amino acid residues and its molecular weight was 77,233 daltons. The content of guanine and cytosine was $48.1mol\%$. The new recombinant plasmid, pTMA322 constructed by inserting the thermostable $\alpha$-amylase gene in the EcoRI site of pIJ322 to produce both the thermostable $\alpha$-amylase and the maltogenic amylase were expressed in the E. coli. The two enzymes expressed from E. coli containing pTMA322 was reacted with the $15\%$ starch slurry at $40^{\circ}C$ for 24hours. The distribution of the branched oligosaccharides produced by the single-step process was of the ratio 50 : 50 between small oligosaccharide up DP3 and large oligosaccharide above DP3.

• 한국미생물·생명공학회지
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• 제21권6호
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• pp.582-587
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• 1993

The extracellular alpha-amylase was purified to homogenity from the culture filtrate of starch grown Sch. castellii CBS 2863. The purified enzyme was glycoprotein with a molecular weight of about 56 kDa. The pH and temperature optimum were 5.5 and 40C, respectively. The enzyme was fairly stable up to 40C and at acid pH range (pH 4.0-7.0). The apparent Km and Vmax of the enzyme toward starch was 1.0mg/ml and 100U/mg protein, respectively. The analysis of amino acid composition was found to be acidic protein. The amino acid sequence of N-terminal peptide consisted of Asp-Val-Ser-Ser-Ala-X-X-Thr-Arg-Ser-Glu-Ser-Ile-Tyr.

• Journal of Ginseng Research
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• 제14권1호
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• pp.21-26
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• 1990

The chemical composition and stabilities of the purified ginseng invertase were investigated. The purified enzyme was found to be a glycoprotein composed of 80.2% protein and 19.7% total sugar. The protein component of the enzyme was composed of acidic amino acid (9.3%), basic amino acid (48.9%), nonpolar amino acid (21.4%), polar amino acid (20.4%) and 6.1% S-containing amino acid. It showed especially high contents of histidine and serine. The enzyme was inactivated almost completely by the treatment with some proteases (papain, pepsin. trypsin, pancreatin and microbial alkaline pretense) and protein denatllrants (8M urea and 6M guanidine-HC1), bolt not with glyrosidase (${\alpha}$-amylase, ${\beta}$-amylase. glcoamylese and cellullase). btonosaccharides sllch as glilrose, fructose, galactose and mannose did not exert any influence on the enzyme activity. The activity of the enzyme was inhibited by Ag+, Mn2+, Hg2+, Zn2+ and Al3+, whereas Ca2+, Mg2+, Ba2+ and Fe3+ gave rather activating effects on the enzyme activity. The enzyme was relatively stable in the VH range of VH 6 and 8, and at the temperatures below 35$^{\circ}C$.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.109-114
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• 1997

The Oomycete Saprolegnia ferax produces an extracellular $\beta$-amylase, Maximum enzyme yield was attained after 7 days of growth in YNB starch medium (pH 6.5) at 25$\circ$C. The amylase was pu- rified 24-fold by ultrafitration, HPLC DEAE column and HPLC gel filtration. The purfied enzyme was a monomeric glycoprotein with a molecular weight of about 44,000 dalton. The pH and temperature optima were 6.5 and 50$\circ$C, respectively. The enzyme was fairly stable up to 50$\circ$C and at acidic pH region (pH 4.0-7.0). The apparent Km and Vmax values of the enzyme against soluble starch were 0.77 mg/ml and 2,174 $\mu$moles/mg protein, respectively. Amino acid analysis indicated that the enzyme was enriched in alanine, glycine, leucine and acidic amino acid. Starch hydrolysis with the enzyme released maltose but not glucose, whereas maltotriose, Schardinger dextrin ($\alpha$-cyclodextrin) and pullulan were not hydrolysed by the enzyme. The enzyme was inhibited by Schardinger dextrin, p-chloromercuribenzoate(PCMB), CU$^{2+}$' and Hg$^{2+}$. Inhibition of the enzyme by PCMB could be reversed by the addition of cysteine and mercaptoethanol.

• Elastomers and Composites
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• 제43권4호
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• pp.221-229
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• 2008

전분을 매트리스 고분자로 하여 아크릴 모노머인 2-ethylhexylacrylate와 methyl methacrylate, acrylic acid를 그래프트 중합하였다. 중합은 라디칼 유화중합에 의하여 전분의 함량을 증가시키면서 수행되었다. 효소인 $\alpha$-amylase 가 전분 대비 0.174% 투입되었을 때 가장 안정한 중합물이 얻어졌으며 전분의 함량이 증가함에 따라 중합물의 유리전이온도가 상승하였다. 전분 함량의 증가에 따라 계내의 -OH기가 많아짐에 따라 중합물의 입자 크기와 점도가 증가하였다. Peel strength는 전분 함량이 증가할수록 -OH기 증가에 의해 중합물이 피착체 표면과의 친화력 상승이 일어나서 증가하였다. 반면 초기 점착력은 전분 함량이 증가할수록 유리전이온도의 증가에 따라 필름의 경도가 증가하면서 감소하였다.