• The Korean Journal of Food And Nutrition
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• 제10권1호
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• pp.117-121
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• 1997

The glucose isomerase productivity of Arthrobacter sp. L-3 was studied. glucose plus xylose showed higher productivity of glucose isomerase than any other carbon sources. Yeast extract showed higher productivity of glucose isomerase than any other nitrogen sources. The optimum culture time for the production of glucose isomerase was 40hrs.

• Microbiology and Biotechnology Letters
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• 제33권2호
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• pp.106-111
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• 2005

To investigate the substrate variety of a putative non-metal dependent isomerase, the tagatose-6-phosphate isomerase (E.C. 5.3.1.26) structural genes (lacB; 510bp and lacA; 430bp) of Staphylococcus aureus were subcloned and co-expressed. Based on the substrate configuration, various aldoses were surveyed for substrate of ketose isomerization. Among the 10 aldoses tested, D-ribose and D-allose were isomerized by the enzyme. The subunit A and B showed more than $95\%$ activity for D-ribose and $75\%$ for D-allose in the presence of 1mM EDTA compared with non-EDTA conditions, which implying tagatose-6-phosphate isomerase is a non-metal dependent isomerase. Each of subunit A or subunit B alone showed no activity for any of the substrates tested. The affinity constant ($K_m$) of tagatose-6-phosphate isomerase against D-ribose and D-allose were 26 mM and 142 mM, respectively.

• Journal of the East Asian Society of Dietary Life
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• 제7권1호
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• pp.35-39
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• 1997

Studies on the glucose isomerase produced by alkalophilic Streptomyces sp. B-2. Glucose Isomerase (E. C. 5.3.1.5) which reversibly catalyzes reaction between D-glucose and D-fructose was demonstrated in cell free extracts of alkalophilic Streptomyces sp. B-2 isolated form soil. The maximum enzyme activity was found at glucose concentration 4(g/$\ell$) , xylose concentration 6(g/$\ell$), magnesium ion 1.0(g/$\ell$), yeast extract concentration 2.0(g/$\ell$), peptone concentration 3(g/$\ell$).

• Journal of the East Asian Society of Dietary Life
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• 제7권1호
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• pp.29-33
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• 1997

The efficient production of glucose isomerase (G. I0.) produced form Arthrobacter sp. L-3 was studied. The optimum culture time of the enzyme was 40hr. The maximum enzyme activity was found at glucose concentration 1%. G. I. activity did not affect inoculum size. The glucose isomerase activity was strongly influenced by the addition of glucose.

• Journal of the East Asian Society of Dietary Life
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• 제10권5호
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• pp.439-444
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• 2000

호알칼리성 방선균 Streptomyes sp. B-2를 Glucose Isomerse 생성을 위해 토양에서 분리했다. Glucose Isomerase(G.I)는 high fructose glucose syrup과 fructose의 생산을 위해서 식품 공업에서 아주 중요시되고 있는 효소이다. 호알칼리성 방선균 Streptomyces sp. B-2가 생성하는 glucose isomerase(G.I.)를 정제하였다. G.I.는 (NH$_4$)$_2$So$_4$분획, DEAE-cellulose, Sephadex G-200 chromatography하여 순수 분리 하였다. 순수분리된 G.I.는 electrophoresis에 의해 확인을 했다. SDS-acrylamide gel electrophoresis에 의해 정제된 효소는 single band를 보여주었다.

• Journal of Microbiology and Biotechnology
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• 제7권1호
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• pp.8-12
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• 1997

In order to overproduce D-xylose isomerase, the Escherichia coli D-xylose isomerase (D-xylose ketol-isomerase, EC 5.3.1.5) gene (xylA) was fused to ${\lambda}P_{L}$ promoter. The promoterless xylA gene containing the ribosome binding site and coding region for D-xylose isomerase was cloned into a site 0.3 kb downstream from the ${\lambda}P_{L}$ promoter on a high copy number plasmid. An octameric XbaI linker containing TAG amber codon was inserted between 33rd codon of ${\lambda}N$ and the promoterless xylA gene. The resulting recombinant plasmid (designated as pPX152) was transformed into E. coli M5248 carrying a single copy of the temperature sensitive ${\lambda}cI857$ gene on its chromosomal DNA. When temperature-induced, the transformants produced 15 times as much D-xylose isomerase as that of D-xylose-induced parent strain. The amount of overproduced D-xylose isomerase was found to be about 60% of total protein in cell-free extracts.

• Microbiology and Biotechnology Letters
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• 제25권1호
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• pp.75-81
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• 1997

Streptomyces chibaensis J-59 did not grow in the culture medium containing only xylose or xylan as a carbon source, because it was defective in xylulokinase production; xylB mutant. S. chibaensis J-59 was able to produce xylanase and $\beta $-xylosidase as well as glucose isomerase. The glucose isomerase in S. chilbaensis J-59 was induced in the medium containing xylan or xylose which could be utilized as an inducer but not sa carbon and energy sources. So we tried to produce glucose isomerase whthout consumption of xylose or xylan as an inducer by using xylB mutant S. chilbaensis J-59. The optimum condition for the production of the glucose isomerase was attained in a culture medium composed of 1% xylan, 0.15% glucose, 1.5% corn steep liquor, 0.1% MaSO$_{4}$ $\CDOT $7H$_{2}$O, and 0.012% CoCL$_{2}$ $\CDOT $ 6H$_{2}$O(pH 7.0). The production of the enzyme reached to a maximum level when the bacteria were cultured for 42 h at 30$\circ $C. The enzyme production in a jar fermentor was increased twice as much as that in a flask culture.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.244-251
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• 1996

Molecular weight and partial amino acid sequence of the cis, 9-cis, 12-octadecadienoate isomerase(linoleate isomerase) of Butyrivibrio fibrisovens A-38 were determined. Linoleate isomerase was isolated from the bac-teria cultured anaerobically and purified by ultracentrifugation in conjunction with Sepharose 6B column chro-matography, Phenyl sepharose 4B column chromatography and fast performance liquid chromatography (EPLC). The isomerase was single polypeptide with 19KD of molecular weight, when determined by SDS-PAGE. Fourteen amino acids sequence of N-terminal of the linoleate isomerase was N-GEIDKYPRIIKQQ determined by Edman method.

• The Korean Journal of Food And Nutrition
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• 제4권2호
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• pp.155-160
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• 1991

Authrobacter sp. L-3이 생성하는 glucose isomerase를 DEAE-cellulose column chromatography법으로 2단계 NaCl농도 구배로 용출함으로서 순수분리하였다. 이것이 SDS-acrylamide gel electrophoresis상에서 단일띠를 보임으로서 매우 잘 분리되었음을 알 수 있었다. Glucose isomerase의 Km값과 Vmax값이 각각 0.175M, 0.29로 얻어졌다. 한편, SDS-acrylamide gel electrophoresis와 Sephadex-G10050에 의한 gel filtration으로부터 분자량이 각각 42,000과 180,000으로 얻어져, 이 효소는 분자량이 42,500인 4개의 subunit로 구성되었음을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제20권6호
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• pp.1018-1021
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• 2010

Metallic and non-metallic isomerases can be used to produce commercially important monosaccharides. To determine which category of isomerase is more suitable as a template for directed evolution to improve enzymes for galactose isomerization, L-arabinose isomerase from Escherichia coli (ECAI; E.C. 5.3.1.4) and tagatose-6-phosphate isomerase from Staphylococcus aureus (SATI; E.C. 5.3.1.26) were chosen as models of a metallic and non-metallic isomerase, respectively. Random mutations were introduced into the genes encoding ECAI and SATI at the same rate, resulting in the generation of 515 mutants of each isomerase. The isomerization activity of each of the mutants toward a non-natural substrate (galactose) was then measured. With an average mutation rate of 0.2 mutations/kb, 47.5% of the mutated ECAIs showed an increase in activity compared with wild-type ECAI, and the remaining 52.5% showed a decrease in activity. Among the mutated SATIs, 58.6% showed an increase in activity, whereas 41.4% showed a decrease in activity. Mutant clones showing a significant change in relative activity were sequenced and specific increases in activity were measured. The maximum increase in activity achieved by mutation of ECAI was 130%, and that for SATI was 190%. Based on these results, the characteristics of the different isomerases are discussed in terms of their usefulness for directed evolution of non-natural substrate isomerization.