• Journal of Microbiology
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• v.35 no.2
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• pp.97-102
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• 1997

Cysteine desulfhydrase (EC 4.4.1.1.) was purified from the culture supernatant of Streptomyces albidoflavus SMF301 by hydroxyapatite, gel filtration and Resource Q ion-exchange chromatography with a purification fold of six identical subunits. The enzyme was stabilized by dithiothreitol and pyridoxal 5'-phosphate during the purification procedures. The optimum pH and temperature were pH 8.6 and 35$^{\circ}C$, respectively. The N-terminal amino acid sequence was identified as A-P-L-P-T-A-D-V-R-S-D-P-G-Y-R-E-W-L-G-E-A-V. The purified cystein desulfhydrase had a high substrate specificity toward cysteine, and exhibited no cystahionine $\gamma$-lyase activity. The $K_m$ value for cysteine was determined to be 0.37 mM.

• BMB Reports
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• v.29 no.4
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• pp.294-299
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• 1996

Glyoxalase I (Ee 4.4.1.5, lactoylglutathione lyase) from Chlamydomonas reinhardtii was purified to homogeneity by ammonium sulfate fractionation, anion-exchange chromatography, hydrophobic interaction chromatography, and affinity chromatography on S-hexylglutathione agarose. The purified enzyme was judged to be homogeneous on SDS-PAGE, and consisted of a single polypeptide chain with a relative molecular weight of 24,000. The enzyme was most active at $40^{\circ}C$ and pH 7.5. It was catalytically most active with methylglyoxal as substrate. A number of properties of the Chlamydomonas glyoxalase I enzyme, such as substrate specificity, molecular mass, kinetic parameters, pi, metal ion effect, have been determined and compared with those reported for preparations from other sources. It had somewhat different characteristics from mammalian enzymes.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.389-393
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• 2001

An $\alpha$-glucosidase inhibitor, CK-4416, was identified from the culture broth of Streptomyces sp. CK-4416. CK-4416, which had some specificity against intestinal disaccharidases, especially sucrase and matlase activities, was purified by adsorption and cationic ion exchange chromatographies. The molecular formula was determined to be $C_{37}H_{63}NO_{30}$ (MW 1001.31) by FAB-MS and NMR analyses. In vitro studies found CK-4416 to show a potent inhibitory activity against sucrase and maltase, but it had low inhibition against $\alpha$-amylase.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.444-455
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• 1991

Two kinds of new lectin fractions (LOA-I, LOA-II) were obtained from loach (Misgurnus spp.) meat by 0.15 M NaCl extraction, salt fractionation, ion exchange and hydroxyapatite column chromatographies. On polyacrylamide gel electrophoresis, LOA-I exhibited one major and a few minor bands, but LOA-II exhibited three minor bands. The partially purified loach lectins agglutinated not only erythrocytes of human B and AB type, rabbit, dog, but also murine splenic lymphocytes. Agglutinability was relatively labile at various pH and stable at increasing temperature, but was not affected by tested several metal ions. By the sugar specificity test, D-glucosamine and metyl-$\beta$-galactopyranose inhibited agglutinating activity at a final concentration of 3 mM. The lectins contained relatively high amounts of aspartic acid, valine and leucine, but sulfur containing amino acids, cystein, methionine and isoleucine were not determined. LOA-I, LOA-II lectins were nonmitogenic toward murine lymphocytes.

• Korean Journal of Microbiology
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• v.26 no.1
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• pp.52-59
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• 1988

A partially purified preparation of L-galactonolactone oxidase which catalyzes the last step of L-ascorbic acid biosynthesis was obtained from Saccharomyces cerevisiae ATCc 26787. The purification procedures included Triton X-100 treatment, protamine sulfate precipitation, ammonium sulfate precipitation, DEAE-Sepharose CL-6B ion exchange chromatography, Sephadex G-150 gel filtration chromatography, and Phenyl-Sepharose CL-4B hydrophobic interaction chromatography. The optimum temperature for the enzyme activity was about $34^{\circ}C$ and the optimum pH was 6.8-7.0. The substrate specificity was confined to L-aldonolactones, L-galactono-1,4-lactone and L-gulono-1,4-lactone. An apparent Km value of 0.294mM with L-galactono-1,4-lactone as a substrate was found. By comparing the substrate specificities of this enzyme with those of isofunctional enzymes of higher plants and animals, it becomes evident that the enzyme of S. cerevisiae ATCC 26787 is rather similar to the L-gulonolactone oxidase of animals than the galactonolactone dehydrogenase of higher plants.

• Journal of Microbiology and Biotechnology
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• v.18 no.4
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• pp.663-669
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• 2008

The solvent-tolerant bacterium Enterobacter sp. VKGH12 is capable of utilizing n-butanol and contains an $NAD^+$-dependent n-butanol dehydrogenase (BDH). The BDH from n-butanol-grown Enterobacter sp. was purified from a cell-free extract (soluble fraction) to near homogeneity using a 3-step procedure. The BDH was purified 15.37-fold with a recovery of only 10.51, and the molecular mass estimated to be 38 kDa. The apparent Michaelis-Menten constant ($K_m$) for the BDH was found to be 4 mM with respect to n-butanol. The BDH also had a broad range of substrate specificity, including primary alcohols, secondary alcohols, and aromatic alcohols, and exhibited an optimal activity at pH 9.0 and $40^{\circ}C$. Among the metal ions studied, $Mg^{2+}$ and $Mn^{2+}$ had no effect, whereas $Cu^{2+},\;Zn^{2+}$, and $Fe^{2+}$ at 1 mM completely inhibited the BDH activity. The BDH activity was not inhibited by PMSF, suggesting that serine is not involved in the catalytic site. The known metal ion chelator EDTA had no effect on the BDH activity. Thus, in addition to its physiological significance, some features of the enzyme, such as its activity at an alkaline pH and broad range of substrate specificity, including primary and secondary alcohols, are attractive for application to the enzymatic conversion of alcohols.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.457-464
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• 2008

An extracellular enzyme (RMEBE) possessing ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferring activity was purified to homogeneity from Rhodothermus marin us by combination of ammonium sulfate precipitation, Q-Sepharose ion-exchange, and Superdex-200 gel filtration chromatographies, and preparative native polyacrylamide gel electrophoresis. The purified enzyme had an optimum pH of 6.0 and was highly thermostable with a maximal activity at $80^{\circ}C$. Its half-life was determined to be 73.7 and 16.7 min at 80 and $85^{\circ}C$, respectively. The enzyme was also halophilic and highly halotolerant up to about 2M NaCl, with a maximal activity at 0.5M. The substrate specificity of RMEBE suggested that it possesses partial characteristics of both glucan branching enzyme and neopullulanase. RMEBE clearly produced branched glucans from amylose, with partial ${\alpha}-(1{\rightarrow}4)$-hydrolysis of amylose and starch. At the same time, it hydrolyzed pullulan partly to panose, and exhibited ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferase activity for small maltooligosaccharides, producing disproportionated ${\alpha}-(1{\rightarrow}6)$-branched maltooligosaccharides. The enzyme preferred maltopentaose and maltohexaose to smaller maltooligosaccharides for production of longer branched products. Thus, the results suggest that RMEBE might be applied for production of branched oligosaccharides from small maltodextrins at high temperature or even at high salinity.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.710-719
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• 2001

Several amino acid transport systems in mammary gland have been characterized during the last few years. These systems may be divided into two broad categories based on whether they are sodium-dependent or $Na^{+}$-independent, and each of these categories is subdivided into 3 groups depending on whether the systems prefer zwitterionic, cationic or anionic substrates. The zwitterion preferring transport processes in mammary gland are $Na^{+}$-dependent system A and $Na^{+}$-independent systems L and T. System $y^{+}$ is a $Na^{+}$-independent transporter of cationic amino acids and $X_{AG^{-}}$ is a $Na^{+}$-dependent system for anionic amino acids. A ($Na^{+}+Cl^{-}$)-dependent system, selective for $\beta$-amino acids has been reported in rat mammary tissue. In addition, there is yet another class of transporters that have still broader specificity. The $Na^{+}$-dependent systems $BCl^{-}$-dependent and $BCl^{-}$-independent and $Na^{+}$-independent system $y^{+}L$ have been reported to mediate the transport of zwitterionic as well as cationic amino acids. Each system has been characterized with respect to its substrate specificity, affinity, kinetics and ion-dependence. Transport of amino acids by mammary tissue is regulated by i) the intracellular substrate concentration, ii) lactogenic hormones and iii) milk stasis. Four of the above transport systems (i.e. A, L, $y^{+}$ and $BCl^{-}$-independent) are up-regulated by lactogenic hormones (insulin, cortisol and prolactin) in mammary gland.

• Journal of Elementary Mathematics Education in Korea
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• v.16 no.2
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• pp.253-267
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• 2012

In this paper, we primarily focus on the perspectives about creative process, which is how mathematical creativity emerged, as one aspect of mathematical creativity and then present a desirable task characteristic to measure and program characteristics to develop mathematical creativity. At first, we describe domain-generality perspective and domain-specificity perspective on creativity. The former regard divergent thinking skill as a key cognitive process embedded in creativity of various discipline domain involving language, science, mathematics, art and so on. In contrast the researchers supporting later perspective insist that the mechanism of creativity is different in each discipline. We understand that the issue on this two perspective effect on task and program to foster and measure creativity in mathematics education beyond theoretical discussion. And then, based on previous theoretical review, we draw a desirable characteristic on instruction program and task to facilitate and test mathematical creativity, and present an applicable task and instruction cases based on Geneplor model at the mathematics class in elementary school. In conclusion, divergent thinking is necessary but sufficient to develop mathematical creativity and need to consider various mathematical reasoning such as generalization, ion and mathematical knowledge.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.145-148
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• 2006

A new functional lipolytic enzyme (AT4) has recently been found from Agrobacterium tumefaciens C58 Cereon using a genome-wide approach. The enzyme has some sequence similarity to E. coli acetyl hydrolase, Emericella nidulans lipase, Moraxella sp. lipase, Acinetobacter lwoffii esterase, and Streptomyces hygroscopicus acetyl hydrolase. However, the sequence similarities are very low (less than $25\%$), suggesting that it is a new lipase/esterase enzyme. ill the present study, intact cell of the A. tumefaciens strain was shown to have lipolytic activity on a tributyrin-LB plate. The AT4 gene was then expressed at a high level in E. coli BL21 (DE3) cells and the enzyme was purified simply by Ni-NTA column chromatography. The purified enzyme showed hydrolytic activity toward p-nitrophenyl caproate, but not toward olive oil, suggesting that the AT4 enzyme was a typical esterase rather than lipase. AT4 esterase had a maximum hydrolytic activity at $45^{\circ}C$ and pH 8.0, when p-nitrophenyl caproate was used as a substrate. It was relatively stable up to $40^{\circ}C$ and at pH 5.0-9.0. Calcium ion and EDT A did not affect the activity and thermal stability of the enzyme. As for substrate specificity, AT4 enzyme could rapidly hydrolyze acetyl and butyl groups from p-nitrophenyl esters and 1-naphthyl esters. In addition, it also released acetyl residues from acetylated glucose and xylose substrates. Therefore, this new esterase enzyme might be used as a biocatalyst in acetylation and deacetylation reactions performed in the fine chemical industry.