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Ashbya gossypii JAG - 13 변이주에 의한 riboflavin 의 생산
나병국,방원기,심문보,염성관 한국농화학회 1992 Applied Biological Chemistry (Appl Biol Chem) Vol.35 No.5
리보플라빈 생산균인 Ashbya gossypii NRRL Y-1056을 이용하여 리보플라빈을 생산하기 위하여, 돌연변이처리에 의한 균주개량을 시도하였으며 이들 변이주를 이용하여 리보플라빈을 생산하기 위한 최적배지조성 및 배양조건을 검토하였다. 최종선발된 4종의 변이주종 Ashbya gossypii JAG-13이 가장 우수하였으며, 탄소원으로 9%의 옥수수기름, 질소원으로는 3%의 젤라톤이 가장 우수하였다. 리보플라빈 생산을 위한 corn steep liquor의 최적농도는 4%였으며, 글리신의 최적농도는 0.3%이였다. 계면활성제중 리보플라빈의 생산촉진효과는 자당지방산 에스테르 계열의 S770이 가장 우수하였으며, 그 최적농도는 0.2%였다. 접종원으로는 24시간 배양액이 종균으로 가장 우수하였으며, 그 최적 접종량은 2% 였다. 또한 최적 배양온도 및 초기 pH는 각각 28℃와 6.5였다. 리보플라빈 생산을 위하여 산소의 공급은 필수적이었으나, 과량의 산소공급은 오히려 리보플라빈의 합성을 저해하였다. 상기의 최적조건에서 생물배양기를 이용하여 Ashbya gossypii JAG-13을 12일간 배양하면 평균 6.9mg/ml의 리보플라빈이 생산되었다.
1996년과 1999년 경기지역 초등학교 학생들에서 유행성이하선염에 대한 면역도 조사
나병국,이주영,고운영,이진수,신구철,이주연,최보율,기모란,양병국,강춘,김우주,김지희 대한감염학회 2001 감염 Vol.33 No.3
Background : Although massive use of live attenuated mumps virus vaccines successfully reduced the incidence of mumps virus infection worldwide, mumps outbreaks have not been completely eliminated, even in vaccinated populations. In recent years, the incidence of mumps has been remarkably increased in Korea. This study was designed to evaluate the recent seroprevalence rate of mumps IgG among children in Kyonggi province at 1996 and 1999. Methods : Study population included students from 8 elementary schools in Kyonggi province. Serum samples were collected twice at 1996 and 1999 and tested for mumps-specific antibody by enzyme-linked immunosorbent assay (ELISA). We also conducted a questionnaire survey on the parents and collected the records including history of vaccination and mumps infection. Results : The seropositive rates against mumps were 89.47% and 89.74% at 1996 and 1999, respectively, and they were not significantly different when compared to age, sex, and region. Although the first vaccination rates were 92.17% and 92.25% at 1996 and 1999, respectively, the second vaccination rates were only 37.89% and 38.03% at 1996 and 1999, respectively. Infection rate showed no significant difference between vaccinated groups and nonvaccinated gropus. Seropositive rate of infected group was higher than that of noninfected group but it was not significantly different between the vaccinated and the nonvaccinated. Conclusions : This study showed the seropositive rate and vaccination against mumps in children. There were no significant relationships between vaccination and infection. Therefore, it seems likely that the vaccination is not fully protective against mumps infection. This study will be helpful for the establishment of guideline for prevention and treatment of mumps in Korea. (Korean J Infect Dis 33: 157∼164, 2001)
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.
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