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Purification and Characterization of Glucoamylase from Aspergillus shirousamii
나병국,양철학,Na, Byung-Gook,Yang, Chul-Hak 생화학분자생물학회 1985 한국생화학회지 Vol.18 No.3
전분, 덱스트린등과 같은 다당류의 비환원성 말단으로부터 glucose 단위로 $\alpha$-1, 4-글루칸 결합을 가수분해하는 글루코아밀라제를 Aspergillus shirousamii로부터 분리하였다. 이 균을 밀기울 배지에 배양시킨 곡자를 증류수로 추출한 다음, DEAE-Sephacel, Con-A Sepharose column을 통과시키고 isoelectric focusing을 시행하여 47.5%의 수율로 19.8배의 활동도 증가를 얻었다. 이 효소의 분자량은 89,000달톤으로 추정되었으며 pI 값은 3.4이었다. 이 효소는 $55^{\circ}C$ 이하에서는 매우 안정하여 1시간 처리에서도 거의 모든 효소활성을 유지하였으나 $70{\circ}C$이상에서는 불안정하여 10분간에 모든 효소활성을 소실하였다. 최대의 가수분해는 15분간 반응시에는 $65^{\circ}C$에서, 60분간 반응시는 $60^{\circ}C$에서 얻어졌다. 이 효소는 pH 4.5에서 가장 안정하였고 최적 pH도 4.5이었다. $Hg^{++}$은 이 효소의 작용을 저해하였으며 $Ca^{++}$은 효소활성 상승에는 영향을 주지 않았으나 효소의 열에 대한 안정성을 크게 향상시켰다. 대부분의 음이온들이 효소활성을 저해하였으며 그중 $B_4{O_7}^{-2}$, $As{O_2}^-$ 및 $S{O_3}^{-2}$가 가장 저해 작용이 커 각각 94% 및 88%의 저해 효과를 주었다. 기질의 종류에 따른 효소반응 속도는 maltotriose가 maltose에 비해 2배 이상의 속도를 보였으며 isomaltose는 0.15배, p-nitrophenyl $\alpha$-D-glucopyranoside는 0.066배로 가수분해속도가 늦었다. 고분자량의 기질중에서느 아밀로펙틴의 가수분해 속도가 가장 빨랐으며 덱스트린이 가장 늦은 속도를 보였다. Glucoamylase ($\alpha$-1,4 glucan glucohydrolase, EC 3.2.1.3) of Aspergillus shirousamii was purified using ammonium sulfate fractionation, DEAE-Sephacel chromatography, affinity chromatography on Concanavalin-A Sepharose 4B and isoelectric focusing. The purification achieved was 19.8 fold from crude extract with a yield of 47.5%. Its molecular weight was estimated to be about 89,000 by Sephadex G-200 gel filtration and SDS-polyacrylamide gel electrophoresis. The pI value of the enzyme was 3.4. The enzyme was stable below $55^{\circ}C$ and retained almost full activity after 1 h. But, it was very labile over $70{\circ}C$. At this temperature, it lost almost all activity witin 10 min. Maximum hydrolysis was occured at $65^{\circ}C$ for 15 min and $60^{\circ}C$ for 60 min, respectively. The enzyme was most stable at pH 4.5, and was more stable in the acidic region than in neutral region. The pH optimum of the enzyme was 4.5 with p-nitrophenyl $\alpha$-D-glucopyranoside as a substrate. The enzyme activity was inhibited by $Hg^{++}$, $Ca^{++}$ markedly increased the heat stability of the enzyme, but it did not affect on the enzyme activity. Most of the anions tested showed the inhibition effect on the enzyme activity. Among these, $B_4{O_7}^{-2}$, $As{O_2}^-$ and $S{O_3}^{-2}$ inhibited remarkably up to 94%, 95% and 88%, respectively. In kinetic studies, the enzyme hydrolyzed maltotriose more than twice of the rate for maltose. Isomaltose and p-nitrophenyl $\alpha$-D-glucopyranoside showed much lower relative rate of hydrolysis than maltose, 0.15 and 0.066, respectively. For the highmolecular-weight substrates, amylopectin showed the highest and dextrin showed the lowest relative rate of hydrolysis, respectively.
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Aspergillus shirousamii 에서 글루코아밀나제의 정제 및 성질의 연구
나병국,양철학 ( Byung Gook Na,Chul Hak Yang ) 생화학분자생물학회 1985 BMB Reports Vol.18 No.3
Glucoamylase (α -1,4 glucan glucohydrolase, EC 3.2.1.3) of Aspergillus shirousamii was purified using ammonium sulfate fractionation, DEAE-Sephacel chromatography, affinity chromatography on Concanavalin-A Sepharose 4B and isoelectric focusing. The purification achieved was 19.8 fold from crude extract with a yield of 47.5%. Its molecular weight was estimated to be about 89,000 by Sephadex G-200 gel filtration and SDS-polyacrylamide gel electrophoresis. The pI value of the enzyme was 3.4. The enzyme was stable below 55℃ and retained almost full activity after 1 h. But, it was very labile over 70℃. At this temperature, it lost almost all activity witin 10 min. Maximum hydrolysis was occured at 65℃ for 15 min and 60℃ for 60 min, respectively. The enzyme was most stable at pH 4.5, and was more stable in the acidic region than in neutral region. The pH optimum of the enzyme was 4.5 with p-nitrophenyl α-D-glucopyranoside as a substrate. The enzyme activity was inhibited by Hg^(++). Ca^(++) markedly increased the heat stability of the enzyme, but it did not affect on the enzyme activity. Most of the anions tested showed the inhibition effect on the enzyme activity. Among these, B₄O_7^(-2), AsO₂^(-2) and SO₃^(-2) inhibited remarkably up to 94%, 95% and 88%, respectively. In kinetic studies, the enzyme hydrolyzed maltotriose more than twice of the rate for maltose. Isomaltose and p-nitrophenyl α-D-glucopyranoside showed much lower relative rate of hydrolysis than maltose, 0.15 and 0.066, respectively. For the high-molecular-weight substrates, amylopectin showed the highest and dextrin showed the lowest relative rate of hydrolysis, respectively. v
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한국에서 분리된 콕사키 바이러스 B3 cDNA의 클로닝 및 전체 염기서열 분석
정윤석(Yoon Suk Jung),김기순(Gee Sun Kim),박정구(Jung Goo Park),이윤성(Yoon Sung Lee),신수연(Soo Yeon Shin),천두성(Doo Sung Chun),지영미(Young Mi Jee),김문보(Mun Bo Kim),나병국(Byung Gook Na),윤재득(Jae Deuk Yoon),이광호(Gwang Ho Lee 대한바이러스학회 2000 Journal of Bacteriology and Virology Vol.30 No.1
We have determined and analyzed the full-length cDNA sequence of a coxsackievirus B3 (CVB3) Korean isolate (CVB3-Korea/97) which has been known as a general human pathogen. The whole genome contains 7,400 nucleotides and has a single large open reading frame with 6,555 nucleotides that encodes a potential polyprotein precursor of 2,185 amino acids. The genome also contains a 5 non-coding region (NCR) of 741 bases and a 3' NCR of 104 bases followed by poly(A) tail. Sequence homologies of nucleotides and deduced amino acids between the CVB3-Korea/97 strain and the prototype (Nancy strain) were 81.7% and 91.5%, respectively. The genes encoding the functional proteins including viral protease and RNA dependent RNA polymerase showed higher homology than those encoding the structural proteins. We have further analyzed the sequences of 5' NCR, VP1 and VP2 of CVB3-Korea/97, which are known as cardiovirulent determining factors at the nucleotide and amino acid levels. Although the CVB 3-Korea/97 strain was isolated from an aseptic meningitis patient without cardiomyopathy, its 234th nucleotide and 165th amino acid were uracil and Asn as same as those of other cardiovirulent strains one. However, the 155th amino acid of VP1, which closely associated with cardiovirulence, was replaced with Arg by single nucleotide substitution from A2916 to T2916. Moreover, additional amino acid substitutions were observed in the flanking region of Asp155. Taken together, amino acid(s) substitution in VP1 may play a critical role in determining cardiovirulence of the CVB3- Korea/97 strain rather than individual nucleotide replacements in the 5' NCR and/or an amino acid substitution in VP2.
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