• BMB Reports
• /
• v.31 no.1
• /
• pp.20-24
• /
• 1998

Thioltransferase, also known as glutaredoxin, is an enzyme that catalyzes the reduction of a variety of disulfides, including protein disulfides, in the presence of reduced glutathione. Thioltransferase was purified from kale through ammonium sulfate fractionation, DE-52 ion-exchange chromatography, Sephadex G-75 gel filtration, and Q-Sepharose ion-exchange chromatography. Its molecular size was estimated to be about 31,000 daltons on SDS-PAGE. The purified enzyme has an optimum pH of about 8.0 with 2-hydroxyethyl disulfide as a substrate. The enzyme also utilizes L-sulfocysteine, L-cystine, bovine serum albumin, and insulin as substrates in the presence of GSH. The enzyme has $K_m$ values of 0.24-0.67 mM for these substrates. The enzyme was partly inactivated after heating at $80^{\circ}C$ or higher temperature for 30 min. The enzyme was stimulated by various thiol compounds such as reduced glutathione, dithiothreitol, L-cysteine, and $\beta$-mercaptoethanol. This is a second example of a plant thioltransferase which was purified and characterized.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.5
• /
• pp.1425-1428
• /
• 2013

The proteasome, which is highly evolutionarily conserved, is responsible for the degradation of most short-lived proteins in cells. Small-molecule inhibitors targeting the proteasome's degradative activity have been extensively developed as lead compounds for various human diseases. An exemplified molecule is bortezomib, which was approved by FDA in 2003 for the treatment of multiple myeloma. Here, using transiently and stably expressed N-end rule model substrates in mammalian cells, we evaluated and identified that salinosporamide A and salinosporamide B effectively inhibited the proteasomal degradation. Considering that a variety of proteasome substrates are implicated in the pathogenesis of many diseases, they have the potential to be clinically applicable as therapeutic agents.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.4.1-4.1
• /
• 2010

In the first part, after discussing works on nacre, a soft-hard composite found in nature, including a simulation on network mimicking nacre [1-4], we talk on a simple model of spider webs, another example of natural soft-hard structure [5]. We demonstrate that the web network is free of stress concentrations because the radial threads are stronger than the spiral threads. In the second part, after reviewing our works on wetting on textured surfaces [6-8], we discuss penetration into textured surface and instability of a liquid film on textured substrates during spin coating [9,10].

• Archives of Pharmacal Research
• /
• v.13 no.2
• /
• pp.132-135
• /
• 1990

Polyhydroxystilbenes including resveratrol were reported to competitively inhibit monoamine oxidase-A-without structural relation with substrates and cynthetic inhibitors for the enzyme. We attempt to explore a plausible mechanism for their inhibitory activity on MAO-A. All the polyhydroxystilbenes tested showed the antioxidant activity on liver homogenate. Furthermore, the antioxidant activity turned out to closely correlate with the MAO-A inhibitory activity.

• Korean Journal of Medicinal Crop Science
• /
• v.20 no.4
• /
• pp.217-221
• /
• 2012

This research was conducted to investigate the influence of various organic substrates on growth and yield of ginseng seedling grown organically in the closed plastic house. The pH and EC of substrates used for organically ginseng cultivation ranged 5.93~6.78 and 0.03~0.15 dS/m respectively. The concentrations $NH_4$-N and $NO_3$-N respectively was 14.01~68.63 mg/L, 5.60~58.83 mg/L. The average quantum of the closed plastic house was range from 10 to 16% of natural light. In July and August, the maximum temperature of the closed plastic house did not exceed 30 and the average temperature was maintained within 25 lower than the field because air conditioning ran. The PPV-1 and PPV-2 bed soil substrates produced higher stem length, stem diameter, shoot fresh weight and leaf area than those of conventional culture. In PPV-2 bed soil substrates, root fresh weight and root diameter was the highest. The root fresh weight of PPV-2 bed soil substrates in closed plastic house was maximum 25% heavier than the conventional cultivation. The results of this experiment will be utilized for making new substrate application for organic ginseng culture in the plastic house.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.9
• /
• pp.3311-3316
• /
• 2011

New poly(arylene ether)s (PAEs) with both transparency and heat-resistance were prepared by a polycondensation of FBPODS, an ordered-sequence aromatic dihalide, and cardo typed aromatic diols containing fluorene and/or adamantane moiety and also non-cardo typed 1,5-naphthalene diol. The resulting polymers had their glass transition temperatures ranged from 202 to $247^{\circ}C$. Based on TGA data, they exhibited excellent thermal stabilities, showing 5% weight loss at $434-487^{\circ}C$. They had low thermal expansion coefficients of 58-59 ppm at temperature range of $50-200^{\circ}C$ as well as good mechanical properties with moduli of 1757-2143 MPa. The optical transmittance for the PAE films was over 70% at 550 nm, except for the PAE that contains naphthalene moiety (30% at 550 nm). They also showed water uptake of about 0.68% regardless of their chemical compositions. Therefore, the newly developed PAEs show strong potential as plastic substrates for flexible devices for display, solar cell and e-paper.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2003.11a
• /
• pp.67-67
• /
• 2003

Minocycline is known to protect neurons from microglia-mediated cell death in many experimental models of brain diseases including ischemic stroke, Huntingtons disease (HD), amyotrophic lateral sclerosis (ALS), traumatic brain injury, multiple sclerosis, and Parkinsons disease. When the activity of caspases was assessed using their fluorescent peptide substrates, activation of caspase-2, 3, 8, and 9 was evident within 2 8 hr following oxidative insult with 0.5 mM hydrogen peroxide in PC12 cells. Minocycline significantly attenuated activation of these caspases up to 18 hr, resulting a significant increase in the cell viability as assessed by MTT assay as well as trypan blue staining. However, cleavage of alpha-spectrin and a cdk5 activator p35, which are known to be substrates for calpain, remained unchanged in the presence of minocycline, suggesting that minocycline did not block caspase-3-independent cell death or necrosis. Moreover, co-treatment with minocycline and a calpain inhibitor calpeptin synergistically inhibited hydrogen peroxide-induced cell death. These data suggest that minocycline directly inhibited apoptosis, but not necrosis, after oxidative insult in PC12 cells.

• Plant Resources
• /
• v.2 no.1
• /
• pp.42-48
• /
• 1999

This study was undertaken to examine the feasibility of black locust (Robinia pseudoacacia) as substrates for several edible mushrooms. For the cultivation of several edible and/or medicinal fungi on black locust, optimum bulk densities, synthetic or semisynthetic additives, natural additives and pretreatment methods were investigated. Fruit body yields of the fungi on various sawdust media composed of different wood species were also analyzed for testing the capability of black locust as a substrate for mushroom production. Mycelial growths decreased proportional when the bulk density increased. The most suitable carbon and nitrogen sources as additives to promote the mycelial growth were sucrose (2%, w/w) and ammonium phosphate (0.2%, w/w) respectively. When corn-powder and beer-waste as natural additives were added to sawdust of black locust showed the significant growth of mycelia. And the optimum mixing ratio was 10:2:1 (sawdust: corn-powder: beer-waste, w/w). Black locust after cold water treatment showed the outstanding mycelial growths. Any significant changes of pH, moisture content (%) and dry-weight losses (%) could not be found among culture substrates (sawdust of black locust, oak and poplar wood) examined before and after harvesting of fruit bodies. Yield of fruit bodies on black locust culture media were comparable with those culture media composed with oak and poplar wood. The present work indicated strongly the potentiality of black locust as raw materials for edible and medicinal mushrooms.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.3
• /
• pp.222-229
• /
• 1994

In order to develop a method of economical production and to reduce energy-consumption in fuel alcohol production, we investigated the fermentation characters of two newly selected thermotolerant yeasts. The RA-74-2 showed stable and superior fermentability between 30 and $40^{\circ}C$ in 20% glucose media in comparison to the industrial strains. The optimum concentration of glucose for economical fermentation at $40^{\circ}C$ was 15-18%, and organic nitrogen was necessary for a satisfactory fermentation. The optimum pH was 4.0 and aeration was adversed for high temperature fermentation. Agitation was an important factor at $40^{\circ}C$ and the addition of magnesium ion 0.2% was required in this experiment. When the inoculum was increased, ethanol productivity as well as the speed of fermentation increased. On the other hand RA-912, which can grow at $48^{\circ}C$, showed similar fermentability between 30-$45^{\circ}C$ in 20% glucose media As the concentration of substrate decreased, fermentation ratio increased at $45^{\circ}C$ (45%, 65%, 95% fermentation ratio in 20%, 15%, 10% glucose media, respectively). Also, requirement of organic nitrogen and magnesium ion in RA-912 was similar in RA-74-2. The optimum pH for fermentation was 5.0, and the effects of agitation were enhanced at $37^{\circ}C$ than at $45^{\circ}C$. As the inoculum was increased, fermentation speed became more enhanced but the ethanol productivity was less affected. RA-912 showed fermentability with various substrates. Among the substrates used, inulin was the most promising substrate for the high-temperature fermentation. When 14.5% inulin was used as the substrate, 93% and 55% fermentation ratios were shown at $37^{\circ}C$ and $45^{\circ}C$, respectively.

• Journal of Microbiology and Biotechnology
• /
• v.6 no.3
• /
• pp.173-178
• /
• 1996

Synergic effects among endo-xylanase, $\beta$-xylosidase, and acetyl xylan esterase of Bacillus stearothermophilus in the hydrolysis of xylan were studied by using birchwood, oat spelt, and acetylated xylan as substrates. Synergism between endo-xylanase and $\beta$-xylosidase was observed on all three substrates tested, indicating that $\beta$-xylosidase enhanced the production of xylose by relieving the end-product inhibition upon endo-xylanase conferred by xylooligomers. Endo-xylanase and $\beta$-xylosidase also showed synergism with acetyl xylan esterase in the hydrolysis of birchwood and acetylated xylan, while no synergic effect was detected in oat spelt xylan hydrolysis. Thus, the hydrolysis of xylan containing acetic acid side chains required the action of acetyl xylan esterase, which eliminated the steric hindrance of the side chains, leading to the better hydrolysis by endo-xylanase and $\beta$-xylosidase , and the acetyl xylan esterase activity was also enhanced by endo-xylanase and $\beta$-xylosidase for the latter enzymes provided acetyl xylan esterase with shorter xylan oligomers, the better substrate for the enzyme.