Ah-Reum Park

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A recombinant β-galactosidase from Caldicellulosiruptor saccharolyticus was purified with a specific activity of 211 U mg−1 by using heat treatment and His-trap affinity chromatography. The native enzyme was an 80-kDa trimer with a molecular mass of 240 kDa. Maximum activity was observed at pH 6.0 and 80ºC, and the half-life at 70ºC was 48 h. The enzyme(More)
Galacto-oligosaccharides have become the focus of a great deal of attention in the field of functional foods, owing to their known health benefits and potential to improve the quality of many foods. Because of these properties, they are currently used as low-calorie sweeteners in fermented milk products, confectioneries, breads, and beverages. In this(More)
We expressed a putative beta-galactosidase from Sulfolobus acidocaldarius in Escherichia coli and purified the recombinant enzyme using heat treatment and Hi-Trap ion-exchange chromatography. The resultant protein gave a single 57-kDa band by SDS-PAGE and had a specific activity of 58 U/mg. The native enzyme existed as a dimer with a molecular mass of 114(More)
A recombinant putative β-galactosidase from Thermoplasma acidophilum was purified as a single 57 kDa band of 82 U mg−1. The molecular mass of the native enzyme was 114 kDa as a dimer. Maximum activity was observed at pH 6.0 and 90°C. The enzyme was unstable below pH 6.0: at pH 6 its half-life at 75°C was 28 days but at pH 4.5 was only 13 h. Catalytic(More)
Since Pt-based catalysts have the disadvantages of high cost, large overpotential loss, and limited long-term stability, there have been various promising alternatives to Pt-based catalysts to improve the catalytic activity towards the oxygen reduction reaction (ORR). We have synthesized iron-nitrogen-doped mesoporous tungsten carbide catalysts (WC-m-FT) by(More)
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