Publications by authors named "Chang-Su Park"

Rare sugars are regarded as functional biological materials due to their potential applications as low-calorie sweeteners, antioxidants, nucleoside analogs, and immunosuppressants. D-Allose is a rare sugar that has attracted substantial attention in recent years, owing to its pharmaceutical activities, but it is still not widely available. To address this limitation, we continuously produced D-allose from D-allulose using a packed bed reactor with commercial glucose isomerase (Sweetzyme IT).

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In this study, we validated the feasibility of an energy weighted algorithm that highlights a characteristic area including the Compton edge as a single peak in a proof-of-principle radiation portal monitor system with a plastic scintillator measuring 50 × 100 × 5 cm. We measured the energy weighted spectra with steel shielding and the dynamic movements of the Cs and Co sources. The results showed that the peak locations of each source could be identified under shielded or dynamic motion conditions, each within a maximum difference of 0.

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Objective: This study was conducted to characterize recombinant α-L-rhamnosidase from Chloroflexus aurantiacus and apply the enzyme in the production of isoquercitrin from rutin.

Results: The α-L-rhamnosidase from C. aurantiacus was cloned and expressed in Escherichia coli BL21 and purified as a soluble enzyme.

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Silver-stained fibrin zymography for separation of protease bands and activity detection using a single substrate gel was designed. The method takes advantage of the nano-scale sensitivity of both zymography and silver staining. After sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) in a gel containing fibrin (protease substrate), the gel was incubated in enzyme reaction buffer and the zymogram gel was silver-stained.

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Objectives: To optimize conversion of rutin to isoquercetin by commercial α-L-rhamnosidase using high hydrostatic pressure (HHP).

Results: The de-rhamnosylation activity of α-L-rhamnosidase for isoquercetin production was maximal at pH 6.0 and 50 °C using HHP (150 MPa).

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To prevent illicit tracking of radionuclides, radiation portal monitor (RPM) systems employing plastic scintillators have been used in ports and airports. However, their poor energy resolution makes the discrimination of radioactive material inaccurate. In this study, an energy weight algorithm was validated to determine (133)Ba, (22)Na, (137)Cs, and (60)Co by using a plastic scintillator.

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The specific activity of recombinant Escherichia coli cells expressing the double-site variant (I33L-S213C) d-psicose 3-epimerase (DPEase) from Agrobacterium tumefaciens was highest at 24 h of cultivation time in Terrific Broth (TB) medium among the media tested. The contents of crude protein and DPEase in recombinant cells at 24 h were 37.0 and 8.

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A purified recombinant enzyme from Spirochaeta thermophila, that is suggested to be a cellobiose 2-epimerase, was a 47 kDa monomer with a specific activity of 29.2 U min(-1) for mannobiose. The epimerization activity of the recombinant enzyme for mannobiose was maximal at pH 7.

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Adjuvants are substances added to vaccines to enhance the immune response of a given antigen. Most of the adjuvants are toxic at certain doses, and toxicity varies in different species. Moreover, there are no standard dosage limits set for adjuvant use in fish vaccines.

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A new screening method for β-(1,3-1,6) glucan hydrolase was developed using a pure β-glucan from Aureobaisidum pullulans by zymography and an LB-agar plate. Paenibacillus sp. was screened as a producer a β-glucan hydrolase on the Trypan Blue-coupled β-glucan LB-agar plate and the activity of the enzyme was analyzed by SDS-β-glucan zymography.

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This study aimed to evaluate the effects of Monascus purpureus-fermented Angelicae gigantis Radix (FAG) on body weight gain, visceral fat accumulation, biochemical markers of obesity, and the mRNA expression levels of various genes involved in adipogenesis in a high-fat-diet (HFD)-induced rat model of obesity. Effect of nodakenin isolated from Angelicae gigantis on 3T3-L1 preadipocyte differentiation was also investigated in vitro. Male Sprague-Dawley rats were randomly divided into five groups (n = 6 per group) based on five dietary categories: HFD control, HFD + 2.

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A putative N-acyl-D-glucosamine 2-epimerase from Caldicellulosiruptor saccharolyticus was cloned and expressed in Escherichia coli. The recombinant enzyme was identified as a cellobiose 2-epimerase by the analysis of the activity for substrates, acid-hydrolyzed products, and amino acid sequence. The cellobiose 2-epimerase was purified with a specific activity of 35 nmol min(-1) mg(-1) for D-glucose with a 47-kDa monomer.

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Pattern recognition receptor (PRR) toll-like receptors (TLRs), antiviral agent interferon (IFN) and the effector IFN stimulated genes (ISGs) play pivotal role in antiviral innate immunity of a host. The present in-vivo experiment was conducted to investigate the role of these innate immune factors in early phase as well as during recovery of viral haemorrhagic septicaemia virus (VHSV) infection by quantitative real-time reverse transcriptase polymerase chain reaction. A less lethal VHSV infection was generated in olive flounder (Paralichthys olivaceus) and was sampled at 3, 6, and 12h post infection (hpi), and 1, 2, 4, and 7 days post infection (dpi).

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The production of compound K and aglycon protopanaxadiol (APPD) from ginsenoside Rd and ginseng root extract was performed using a recombinant β-glycosidase from Pyrococcus furiosus. The activity for Rd was optimal at pH 5.5 and 95°C with a half-life of 68 h at 95°C.

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A putative L-rhamnose isomerase (RhaA) from Thermotoga maritima was purified with a specific activity of 55 U/mg by His-Trap affinity chromatography. The native enzyme was estimated as a 46 kDa tetramer by gel filtration chromatography. The half-lives of the enzyme at 75, 80, 85, 90 and 95°C were 773, 347, 187, 118, and 65 h, respectively, indicating that it is the most thermostable of all RhaAs.

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Prokaryotes can use a variety of sugars as carbon sources in order to provide a selective survival advantage. The gene z5688 found in the pathogenic Escherichia coli O157:H7 encodes a "hypothetical" protein of unknown function. Sequence analysis identified the gene product as a putative member of the cupin superfamily of proteins, but no other functional information was known.

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The specific activity and catalytic efficiency (k(cat)/K(m)) of the recombinant putative protein from Providencia stuartii was the highest for D-lyxose among the aldose substrates, indicating that it is a D-lyxose isomerase. Gel filtration analysis suggested that the native enzyme is a dimer with a molecular mass of 44 kDa. The maximal activity for D-lyxose isomerization was observed at pH 7.

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A recombinant D-lyxose isomerase from Providencia stuartii was immobilized on Duolite A568 beads which gave the highest conversion of D-fructose to D-mannose among the various immobilization beads evaluated. Maximum activities of both the free and immobilized enzymes for fructose isomerization were at pH 7.5 and 45 degrees C in the presence of 1 mM Mn(2+).

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Ginsenosides are the principal components responsible for the pharmaceutical activities of ginseng. The minor ginsenosides, which are also pharmaceutically active, can be produced via the hydrolysis of the sugar moieties in the major ginsenosides using acid hydrolytic, heating, microbial, and enzymatic transformation techniques. The enzymatic method has a profound potential for ginsenoside transformation, owing to its high specificity, yield, and productivity, and this method is increasingly being recognized as a useful tool in structural modification and metabolism studies.

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The conversion of beta-carotene to retinal by a recombinant beta-carotene 15,15'-dioxygenase (Blh protein) from an unculturable marine bacterium was optimized in aqueous solution. Toluene was optimal solvent for the dissolution of beta-carotene and the optimal solution for the conversion reaction contained 2.4% (w/v) Tween 20, 0.

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The Lys residue at position 108 of human beta-carotene 15,15'-monooxygenase is located on the outside surface of the active tunnel of the enzyme. Hydrophobic mutations (K108F and K108L) at this position substantially decreased the affinity of the enzyme for substrates with ionone rings at both ends, such as alpha-carotene, beta-carotene, and beta-cryptoxanthine. In contrast, these mutations had little effect on the affinity of the enzyme for substrates with one ionone ring and one open-chain end, such as beta-apo-4'-carotenal and beta-apo-8'-carotenal.

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The activity of ribose-5-phosphate isomerases (RpiB) from Clostridium difficile for D-ribose isomerization was optimal at pH 7.5 and 40 degrees C, while that from Thermotoga maritima for L-talose isomerization was optimal at pH 8.0 and 70 degrees C.

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Two enzymes, L-arabinose isomerase and mannose-6-phosphate isomerase, from Geobacillus thermodenitrificans produced 118 g/liter L-ribose from 500 g/liter L-arabinose at pH 7.0, 70 degrees C, and 1 mM Co(2+) for 3 h, with a conversion yield of 23.6% and a volumetric productivity of 39.

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A recombinant beta-glucosidase from Caldicellulosiruptor saccharolyticus DSM 8903 with a specific activity of 13 U/mg was purified by heat treatment and His-Trap affinity chromatography and identified as a single 54 kDa band on SDS-PAGE. The molecular mass of the native enzyme was 108 kDa as a dimer by gel filtration. beta-Glucosidase showed optimum activity at pH 5.

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A recombinant putative glycoside hydrolase from Caldicellulosiruptor saccharolyticus was purified with a specific activity of 12 U mg(-1) by heat treatment and His-Trap affinity chromatography, and identified as a single 56 kDa band upon SDS-PAGE. The native enzyme is a dimer with a molecular mass of 112 kDa as determined by gel filtration. The enzyme exhibited its highest activity when debranched arabinan (1,5-alpha-L-arabinan) was used as the substrate, demonstrating that the enzyme was an endo-1,5-alpha-L-arabinanase.

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