• Analytical Science and Technology
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• v.20 no.5
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• pp.393-399
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• 2007

In principle, the blood galactose level may be determined conveniently with a strip-type biosensor similar to that for glucose. In this study, we describe the development of a disposable galactose biosensor strip for point-of-care testing. The sensor strip is constructed with screen-printed carbon paste electrode (SPCE) and sample amount (< $100{\mu}L$). The developed strip the galactose level in less than 90 s using bienzymatic system of galactose oxidase (GAO) and horseradish peroxidase (HRP). The effects of pH, mediator (1,1-ferrocenedimethanol) concentration, ratio of enzymes, and applied potential were determined preliminarily with glassy carbon electrodes, and optimized further with the strip-type electrodes. The sensor exhibits linear response in the range of $0{\sim}400{\mu}M$ ($r^2$ = 0.997, S/N = 3). Since a low working potential, in principle, the fabricated disposable galactose biosensor has -100 mV (vs. Ag/AgCl), it is applied for the detection of galactose, interfering responses from common interferents such as ascorbic acid, uric acid and acetaminophen could be minimized. The sensor has been used to determine the total galactose level in standard samples with satisfactory reproducibility (CV = 5 %).

• KSBB Journal
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• v.11 no.3
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• pp.270-275
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• 1996

Heterologous expression of glucose oxidase gene using recombinant yeast has been carried out. Polymerase chain reaction was conducted to obtain the gene encoding glucose oxidase from Aspergillus niger and sequence comparison indicated the cloned 1.9kb DNA fragment appeared to be the glucose oxidise structural gene containing a signal sequence for extracellular location. Transforming shuttle vector was constructed with YEp352 to express the cloned glucose oxidase gene under the control of either GAL1 or GAL10 promoter. Plate assay of recombinant yeasts has shown that GAL1 promoter was more effective in yielding glucose oxidise than GAL10 promoter. Among the five different concentrations of galactose tried, 1% galactose showed the highest induction of glucose oxidase. Cellular localization experiment of recombinant enzyme using spheroplast revealed that most of enzymes (80%) were secreted into culture media in contrast to A. niger. There is no difference in heat-stability of recombinant enzyme up to $50^{\circ}C$ compared to the glucose oxidase from A. niger However, a dramatic reduction of enzyme activity was observed in both enzymes at $60^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.6
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• pp.792-796
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• 1993

The synthesis alcohol-oxidase[EC 1.1.3.13] was investigated in the yeasts, Candida boidinii CBS 8106 and C. boidinii CBS 2428, during growth on different carbon sources. Alcohol-oxidase was undetectable in all strains submitted to the test in the mineral salts medium containing 1.0% glucose, but its production was rapidly increased when the carbon source was changed glucose to 1.0% methanol after 24hrs of incubation. When cells were grown on the various carbon sources (glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), the alcohol-oxidase activity was undetected. These carbon sources together with methanol yielded far better synthesis of alcohol-oxidase than in the case of carbon sources alone. Alcohol-oxidase was active towards alcohol of shorter alkyl-chain length than C5 and unsaturated alcohols. Its affinity for these alcohols decreased with the increasing length of the alkyl-chain. The apparent Km values for the methanol of Candida boidinii CBS 8106 and C. boidinii CBS 2428 were 1.96 and 1.21, respestively.

• Journal of Electrochemical Science and Technology
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• v.11 no.3
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• pp.310-317
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• 2020

A development of disposable strip-type galactose sensor for point-of-care testing (POCT) was studied, which was constructed using screen-printed carbon electrodes. Galactose levels were determined by the redox reaction of galactose oxidase in the presence of potassium ferricyanide as an electron transfer mediator in a small sample volume (i.e., less than 1 µL). The optimal performance of biosensor was systematically designated by varying applied potential, operating pH, mediator concentration, and amount of enzyme on the electrode. The sensor system was identified as a highly active for the galactose measurement in terms of the sensitivity (slope = 4.76 ± 0.05 nA/µM) with high sensor-to-sensor reproducibility, the linearity (R² = 0.9915 in galactose concentration range from 0 to 400 µM), and response time (t_95% = <17 s). A lower applied potential (i.e., 0.25 V vs. Ag/AgCl) allowed to minimize interference from readily oxidizable metabolites such as ascorbic acid, acetaminophen, uric acid, and acetoacetic acid. The proposed galactose sensor represents a promising system with advantage for use in POCT.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.435-443
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• 1989

The regulation of the synthesis of alcohol-oxidase(E. C. 1. 1. 3. 13) was investigated in the methanol-utilizing yeasts during growth on different carbon sources. For this experiment, Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 were cultured in mineral salt medium by changing its carbon sources. The production of alcohol-oxidase was varied by the carbon sources. For example, alcohol-oxidase was undetectable in all strains submitted to the test in the medium with glucose, but its production was rapidely increased when the carbon source was changed from glucose to methanol after 48hrs of incubation. Moreover, this enzyme was not synthesized during growth on the primary aliphatic alcohols alone(ethanol, propanol, butanol or pentanol) or on the mixed substrates(0.5% methanol+0.5% primary aliphatic alcohols). When cells were grown on the various carbon sources(glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), The alcohol-oxidase activity was detected a very little amounts. These carbon sources together with methnol yieled far better synthesis of alcohol-oxidase than in case of carbon sources alone. Especially, the alcohol-oxidase activity of the cells grown on sorbose, lactose or lactic acid together with methanol was far better or similar than that of cells grown on methanol alone. The apparent Km values for the methanol of Pichia pastoris CBS 2612 and Pichia pastoris CBM 10 enzymes were 1.92 and 210 mM, respectively. It is also active towards alcohols of shorter alkyl-chain length than $C_7$, insaturated alcohols(allylalcohol, crotyl-alcohol) and secondary alcohols (iso-amylacohol, iso-butylalcohol). The affinity of alcohol-oxidase for this alcohols decreased with the increasing length of the alkyl-chain.

• The Korean Journal of Zoology
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• v.26 no.3
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• pp.155-170
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• 1983

The primary concern has been focused on the response and adaptation of mouse fibroblast tumor cells to heat-shock in the level of membrane surface proteins, using two labeling techniques, lactoperoxidase-catalyzed iodination and galactose oxidase-sodium borohydride. Cells arrested in $G_1$ phase exhibited the highest level of LETS protein and high molecular proteins than did cells passing through $G_1/S, S, G_2$ and M, and unsynchronized cells. Confluent cells were found to show an increase in 125K proteins and a decrease in 130K and 100K proteins selectively. The adaptation processes of tumor cells after heat-shock were observed. All the proteins above 80K were reduced immediately after heat-shock, whereas 70K protein increased markedly 24 hours after heat-shock. The 70K protein and high molecular proteins returned to normal level in 48 hours. The 70K protein was found to be trypsin-sensitive and was similarly labeled by galactose-oxidase as well as by lactoperoxidase. It was, therefore, concluded that 70K protein is glycoprotein located on the surface membrane and might be the HSP 70. Possible function of heat-shock protein on the surface membrane and the relation of this protein to differential heat-sensitivity of tumor cells are discussed.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.461-467
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• 1989

The regulation of the synthesis of alcohol-oxidase (E.C.1.1.3.13.) was investigated in the methanol-utilizing yeasts during growth on different carbon sources. For this experiment, Hansenula polymoypha CBS 4132, Hansenula polymoypha CBM 11 and Hansenula polymoypha Cooney were cultured in mineral salt medium by changing its carbon sources. The production of alcohol-oxidase was varied by the carbon sources. For exmaple, alcohol-oxidase was undetectable: in all strains submitted to the test in the medium with glucose, but its production was rapidly increased when the carbon source was changed from glucose to methanol after 30 hrs of incubation. Moreover, this enzyme was not synthesized during growth on the primary aliphatic alcohols alone (ethanol, propanol, butanol or pentanol) or on the mixed substrates (0.5% methanol + 0.5% primary aliphatic alcohols). When cells were grown on the various carbon sources (glucose, xylose, lactose, glycerol, galactose, saccharose, sorbose, lactic acid or acetic acid), the alcohol-oxidase was about one-tenth of the activity found in cells grown on methanol alone. These carbon sources together with methanol yielded far better synthesis of alcohol-oxidase than in case of carbon sources alone. Especially, the alcohol-oxidase activity of the cells grown on lactose or lactic acid together with methanol was far better or similar than that of cells grown on methanol alone. The synthetic activity of alcohol-oxidase of Hansenula polymoypha CBS 4132 was the strongest among the three strains tested in every respect.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.471-471
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.765-766
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• 2005

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.373-381
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• 1994

An actinomycete strain, HSL-613 was isolated -from soil and identified by International Streptomyces Project (ISP) and chemotaxonomic methods. The spore chain of the strain HSL-613 appears in a spiral shape, and its spores are spherical shape with smooth surface. The cell wall contains LL-diaminopimelic acid (DAP). Menaquinone MK-9 (H$_{6}$, H$_{8}$) and iso- and anteiso-branched fatty acids were detected from whole cell extract. Sugars identified from whole cell extract include galactose, glucose, mannose and ribose, which are distinct from general sugar patterns of Streptomyces. Average G+C content in the chromosome is 59%. 5S rRNA of HSL-613 consists of 120 nucleotides as determined by comparing with that of a type strain Streptomyces griseus subsp. KCTC 9080. Through morphological, physiological, and chemical characterization, HSL-613 was identified and named as Streptomyces sp. HSL-613.