• The Korean Journal of Physiology
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• 제18권2호
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• pp.163-169
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• 1984

Vanadate가 Na-K-ATPase의 최적 PH에 영향을 미치는 기전에 효소의 $Na^+$과 $K^+$의 결합부위가 관여하는지를 밝히기 위하여 가토 신피질 microsome을 이용하여 실험해서 다음과 같은 결과를 얻었다. 1) $5{\times}10^{-6}M$ vanadate 존재시 Na-K-ATPase의 추적 PH가 6.8로 이동하였다. 2) PH 6.8과 7.4에서 Na-K-ATPase활성의 비는 vanadate농도가 증가함에 따라 증가하였다. 3) Vanadate 존재시에도 용액의 $Na^+$농도가 50mM 이하일 때는 pH 7.4에서의 효소활성이 6.8보다 높았고 오히려 그 비는 대조군보다 증가하였다. 4) $K^+$농도가 7mM 이하일 때는 vanadate 존재시도 Na-K-ATPase의 활성이 PH 7.4에서 더 높았다. 5) 5mM $K^+$존재하에서도 vanadate농도를 $10^{-5}M$로 증가시키면 최적 pH는 6.8로 이동하였다. 6) $K^+-pNPPase$활성은 PH가 낮을수록 증가하였고 $10^{-7}M$ vanadate에 의한 억제 정도는 PH가 낮을수록 감소하였다. 이상의 결과로 볼때 vanadate 존재시 Na-K-ATPase의 최적 PH는 6.8로 이동하였으며 이것은 PH가 낮아 펄 때 나타나는 vanadate자체의 성질 변화 때문은 아니며 vanadate 존재시 pH가 효소의 $Na^+$과 $K^+$결합부위에 영향을 주어 나타나는 것으로 생각된다.

• KSBB Journal
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• 제28권3호
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• pp.170-176
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• 2013

The purpose of this study was to determine optimum condition of Pavlova lutheri and Phaeodactylum tricornutum. Detailed studies were carried out on the effects of various wavelengths of light-emitting diodes (LEDs), light intensities and air flow rations. For the Pa. lutheri, cell growth rates and maximum cell concentrations were similar regardless of wavelengths and air flow rates. Among the different light intensities, cell concentration increased when light intensity of red LED increased. For Ph. tricornutum, red LED was found to be the most effective light source, and light intensity of 3,100 Lux resulted in the most effective for the cultivation of Ph. tricornutum. Different air flow rates were tested to overcome shading effects due to denser cell concentration in the solution. Aeration of 0.8 vvm was determined to be the optimum aeration rate for the cultivation of Ph. tricornutum. Especially, five and two times greater cell concentrations of Pa. lutheri and Ph. tricornutum, respectively, were observed when air was applied.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2984-2988
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• 2009

A gene (PH0311) encoding a hypothetical protein from the genome sequence data of the hyperthermophilic archaeon Pyrococcus horikoshii OT3 was cloned and over-expressed in Escherichia coli. The purified recombinant protein was found to possess FAD-dependent NADH oxidase activity, although it lacked sequence homology to any other known general NADH oxidase family. The product of the PH0311 gene was thus designated PhNOX (NADH oxidase from Pyrococcus horikoshii), with an estimated molecular weight of 84 kDa by gel filtration and 22 kDa by SDS-PAGE, indicating it to be a homotetramer of 22 kDa subunits. PhNOX catalyzed the oxidation of reduced ${\beta}$-NADH with subsequent formation of $H_2O_2$ in the presence of FAD as a cofactor, but not ${\alpha}$-NADH, ${\alpha}$-NADPH, or ${\beta}$-NADPH. PhNOX showed high affinity for ${\beta}$-NADH with a Km value of 3.70 ${\mu}$M and exhibited optimum activity at pH 8.0 and 95$^{\circ}C$ as it is highly stable against high temperature.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2001년도 Proceeding of KIN-CIN Joint Symposium 2001 on Satellite Navigation/AIS, lntelligence , Computer Based Marine Simulation System and VDR
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• pp.89-99
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• 2001

Optimum Ship Routing can be defined as “The selection of an optimum track for a transoceanic crossing by the application of long-range predictions of wind, waves and currents to the knowledge of how the routed vessel reacts to these variables”. This paper treats the methodology how to serve optimum ship routing problem by network modeling and reveals the validity of the network model by some numerical experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.102-104
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• 1989

The characteristics of stearic acid and PDA (pentacosaDiyonicAcid) LB films were studied using the XRD spectra for regularity of layers and ellipsometer for the total thickness of multilayer films. From the experiments of varying the PH and temperature, it was found that the stability of monolayer on the water subphase was very sensitive to its PH and temperature. The optimum condition of PH for the stable stearic acid LB film was 6$\sim$6.5. The PDA LB films were stable at the lower temperature than room temperature: we obtained very uniform PDA LB films at 12$^{\circ}C$.

• 한국식품조리과학회지
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• 제4권2호
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• pp.65-69
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• 1988

세 가지 액체배지를 사용하여 Berkeley대학 Dr. Bjeldanes Lab에서 isolate된 F. moniliforme을 생육시킨 결과 Czapek-Dox medium에서 Fusarin C생성량이 가장 높았으며 옥수수에 비하면 약 1/10정도의 양인 것으로 나타났다. 그리고 Czapek-Dox medium의 경우 $28^{\circ}C$에서 2주간 배양한 때에 Fusarin C의 생성량이 가장 많았으며 옥수수의 경우는 28$^{\circ}C$에서 1주간 배양한 때에 가장 높았다. 또한 Czapek-Dox medium의 initial PH가 6.5인 때에 Fusarin C의 생성량이 최대이었으며 6.3, 5.9인 때도 다른 PH보다 월등히 높은 양이 생성됨을 확인할 수 있었다.

• Mycobiology
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• 제48권3호
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• pp.195-203
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• 2020

Marine yeasts have tremendous potential in industrial applications but have received less attention than terrestrial yeasts and marine filamentous fungi. In this study, we have screened marine yeasts for amylolytic activity and identified an amylase-producing strain PH-Gra1 isolated from sea algae. PH-Gra1 formed as a coral-red colony on yeast-peptone-dextrose (YPD) agar; the maximum radial growth was observed at 22 ℃, pH 6.5 without addition of NaCl to the media. Based on the morphology and phylogenetic analyses derived from sequences of internal transcribed spacer (ITS) and a D1/D2 domain of large subunit of ribosomal DNA, PH-Gra1 was designated Sporidiobolus pararoseus. S. pararoseus is frequently isolated from marine environments and known to produce lipids, carotenoids, and several enzymes. However, its amylolytic activity, particularly the optimum conditions for enzyme activity and stability, has not been previously characterized in detail. The extracellular crude enzyme of PH-Gra1 displayed its maximum amylolytic activity at 55 ℃, pH 6.5, and 0%-3.0% (w/v) NaCl under the tested conditions, and the activity increased with time over the 180-min incubation period. In addition, the crude enzyme hydrolyzed potato starch more actively than corn and wheat starch, and was stable at temperatures ranging from 15 ℃ to 45 ℃ for 2 h. This report provides a basis for additional studies of marine yeasts that will facilitate industrial applications.

• 미생물학회지
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• 제17권4호
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• pp.187-192
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• 1979

Dennis (1972) reported that Trichosporon cutaneum FRI-425 from the petioles of Pheum rhamponticum var, had showed the celluloytic activity. Chun (1977) also suggested that Trichoporon pullulons 225 isolated from the saline water of the Yeoung San River had a similar properties. However, the assay conditions for enzyme activity were not yet investigated. Thus, the present work was undertaken to examine some conditions for CMCase activity and at the same time to compare the activities of crude enzyme produce from above two species of Trichosporon pullulans. The results are as follows; 1. The maximum production of total reducing sugar by crude enzyme of Tr. pululans was after 30 minutes, whereas that of Tr. cutanuem FRI-425 was after 90 minutes. This fact showed that the reaction velocity of enzyme from Tr. pullulans 225 was more faster than that of Tr. cutaneum FRI-425. 2. Two species showed a similar trend to increase the production of reducing sugar in proportion to the increment in substrate concentration and to arrive at maximum level at lmg/ml of substrate concentration. However, Tr. pullulans 225 produced more $50{\mu}g$ of reducing sugar compared to Tr. cutaneum. 3. The optimum PH for CMCase activity is 5.0 for Tr. pullulans 225 as well as Tr. cutaneum FRI-425, and PH stability lie within the range of 6 and 8. In the activity and stability of enzyme on PH changes, enzyme of Tr. cutaneum FRI-425 was more unstable than that of TY. pullulans 225. 4. The optimum temperature for CMCase activity was $40^{\circ}C$, and enzyme activity from Tr. pullulans 225 was more sensitive to temperature changes compared with that of TY. cutaneum. The heat stability was within $40^{\circ}C$, but that was rapidly decreased above $40^{\circ}C$. In comparison of the heat stability for enzyme of Tr. cutaneum FRI-425 with that of Tr. pullulans 225 at the same temperature of $80^{\circ}C$, the former was some 10 percent more stable than the latter.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.101-104
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• 1997

Lactic acid production from ${\alpha}$-cellulose by simultaneous saccharification and fermentation (SSF) was studied. The cellulose was converted in a batch SSF using cellulase enzyme Cytolase CL to produce glucose sugar and Lactobacillus delbrueckii to ferment the glucose to lactic acid. The effects of temperature, PH, yeast extract loading, and lactic acid inhibition were studied to determine the optimum conditions for the batch processing. Cellulose was converted efficiently to lactic acid, and enzymatic hydrolysis was the rate controlling step in the SSF. The highest conversion rate was obtained at 46$^{\circ}C$ and pH 5.0. The observed yield of lactic acid from ${\alpha}$-cellulose was 0.90 at 72 hours. The optimum pH of the SSF was coincident with that of enzymatic hydrolysis. The optimum temperature of the SSF was chosen as the highest temperature the microoraganism could withstand. The optimum yeast extract loading was found to be 2.5g/L. Lactic acid was observed to be inhibitory to the microorganisms' activity.

• 한국식품영양과학회지
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• 제23권3호
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• pp.490-495
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• 1994

Acid phosphatase (EC3.1.3.2) from carrots was partially purified by ammonium sulfate fractionation (30%-80%), Sephacryl S-200 gel filtration, cm-Sepharose CL-6B and DEAE -Sephacel ion exchange chromatography. The optimum ph and temperature of acid phosphatase from carrots were pH 5.5 and 55$^{\circ}C$, respectively. The enzyme was most stable at ph 6.0 and relatively unstable below pH 4.0 . The activation energy of the enayme was determined to be 10.6kcal/mole. The enzyme utilized p-nitrophenyl phosphate as a substrate among tested possible substrates, whereas it hydrolyzed 5' -IMP and 5'-GMP poorly. The Michaelis -Menten constant(Km) of the enzyme with p-nitrophenyl phosphate as a substrate was identified as 0.55mM. Amongtested metal ions and inhibitors, Al+++ Zn++, Cu++ , fluoride, metavanadate and molybdate ions inhibited the enzyme activity drastically.