• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.12-18
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• 2008

Antioxidative activity and inhibitory activity of angiotensin I converting enzyme(ACE), aminopeptidase N(APN) and $\alpha$-amylase were investigated in the methanol extracts from 25 fern plants native to Jeju Island, in order to screen the plant species containing bioactive materials for functional foods or medicines. The antioxidative activity was higher in Cytomium fortunei(41.9%) and Rumohra standishii(34.1%) than in leaves of Thea sinensis(30.9%), a small tree for antioxidative beverage. Inhibitory activities of ACE and APN were relatively high in Cytomium fortunei as 26.7% and 28.2% respectively. $\alpha$-Amylase inhibitory activity was higher than 50% in 10 species. Particularly, Cytomium fortunei(87.4%) and Dryopteris erythrosora(71.6%) showed the inhibitory activities higher than those of other form plants. Of 25 fern plants investigated here, Cytomium fortunei showed not only the highest antioxidative activity but also the highest inhibitory activity of ACE, APN and $\alpha$-amylase. It suggests that Cytomium fortunei could be potentially used as a resource of bioactive materials for fuctional foods or medicines.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.31-45
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• 1991

Present experiment was performed in order to establish the optimal reaction conditions for determination of urinary AAP and GRS activities and to investigate the applicability of urinary AAP and GRS in nephrotoxicity test in rat. The results were as follows ; 1. The optimal pH of phosphate buffer for determination of urinary AAP activity was 7.8. 2. The Michaelis constant of urinary AAP ranged from 0.8 to 1.0mmol/$\ell$ 3. The optimal wave length for determination of urinary GRS activity was 405nm. 4. The optimal pH of acetate buffer for determination of urinary GRS activity was 5.6. 5. The Michaelis constant of urinary GRS ranged from 0.65~0.79mmo1/$\ell$. 6. The AAP activities in gel-filtered samples were significantly higher than those in crude samples. Mean values of AAP activities in gel-filtered samples and crude samples were 29$\pm$20 and 20$\pm$13U/$\ell$, respectively. 7. There was not significant difference between gel-filtered samples and crude samples in urinary GRS activities. Mean values of GRS activities in gel-filtered samples and crude samples were 57$\pm$40 and 56$\pm$39U/$\ell$, respectively. 8. Limits of linearity of urinary AAP and GRS activities were 2.0 and 3.6U/$\ell$, respectively. 9. Within-run imprecisions of the assays, were acceptable, as the coefficients of the AAP activities ranged from 5.5 to 6.3% and those of GRS activities ranged from 1.4 to 6.2%, respectively. 10. Urinary AAP excretion was 675$\pm$227mu/24hrs.kg before administration of potassium dichromate, and increased significantly to 4246$\pm$2567mU/24hrs.kg within 24 hours after administration of potassium dichromate. 11. Urinary GRS excretion did not increase significantly after administration of potassim dichromate. 12. From these findings it is concluded that urinary AAP excretion is early and sensitive Indicator to detect kidney damage in nephrotoxicity experiment.

• Toxicological Research
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• v.14 no.3
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• pp.365-370
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• 1998

To evaluate the renal toxicity of the antitumor agent, p-{N,N,-Bis(2-chloroethyl)amino}-4-phenyl acetyl-amino-2,6-piperidinedione(CK-15), rats were treated with CK-15 (acute: 50mg/kg. i.p., single and subacute: 5mg/kg, i.p., daily for 7 days). The changes in the body weight, water consumption, kidney weights and urine volume after and during the treatment were observed. The concentrations of urinary creatinine and portein, the activities of N-acetyl-${\beta}$-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), ${\gamma}$-glutamyl transpeptidase (${\gamma}$-GT) and lactate dehydrogenase (LDH) in 24hr urine were also determined. The body weight, water consumption, and urine volume were decreased after the acute and subacute administration. However the weights of kidney were not changed after the treatments. The excretion of creatinine was significantly decreased 1 day after acute administration but, returned to the control value. In subactute administration, the excretion of creatinine was gradually decreased. However, the protein excretion did not changed in both treatment. Those indicate that CK-15 might decrease the metabolic rate of muscle. THe urinary activities of NAG, AAP, ${\gamma}$-GT, and LDH were significantly affected bythe drug treatment. The urinary activities of NAG, AAP and ${\gamma}$-GT were significantly increased 1 day after the acute administration and then returned to the control value. However, the urinary activities of LDH were not changed in acute treatment. In subacute treatment, although the urinary activities of NAG were not changed, those of AAP and ${\gamma}$-GT were significantly increased 2.3 times at 3 days during the subacute administration. Also the urinary activities of LDH were significantly increased at 7 day after the administration. These results indicate that the high and subacute administration might induce a damage in the kidney cells. Furthermore the present results suggest that the toxic effects of CK-15 might be due to the accumulation of the metabolites.

• The Korean Journal of Mycology
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• v.14 no.2
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• pp.93-99
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• 1986

Isozyme patterns of leucine aminopeptidase, esterase and protein from 16 isolates of Ganoderma lucidum were observed by electrophoresis for characterization of the isolates. Even in the same isolate, the patterns of the isozymes from mycelium and cap were different. The esterase patterns from the mycelium could differentiate the isolates. Of 16 isolates, four isolates showed identical patterns. It was assumed that these had the same genetic background.

• The Korean Journal of Mycology
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• v.16 no.4
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• pp.235-241
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• 1988

This study was carried out to investigate some morphological characters of fruit bodies of Ganoderma lucidum and to classify the fungus on the bases of the genetic character. Some of the isolates of the fungus which originally have the kidney-shaped fruit bodies produced the antler-shaped fruit bodies on artificial media and the latter characters were inherited. Pattern of the pileus surface and thickness of the pileus of the fruit bodies were also considered to be hereditary. Although morphology of the pileus margin and fruiting mode of the fungus were variable among the isolates, they were greatly influenced by environment conditions. Ganoderma lucidum could be classified into two groups and four strains according to the morphology of the fruit bodies on artificial cultivation media. Electrophoretic patterns of esterase, peroxidase, leucine aminopeptidase(LAP) and proteins of fruit bodies and mycelia of Ganoderma lucidum showed high genetic variation. Isozyme patterns of esterase of the mushroom mycelia were applicable for the classification of strains of the fungus. Patterns of proteins, leucine aminopeptidase and peroxidase did not indicate any genetic relation among the fungus strains.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.479-484
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• 1992

This study was undertaken to determine the effects of cultural conditions on cell growth and casein hydrolysis for cell production in order to add Micrococcus sp. LL3 as a potential agent for industrial application with aim of shortening ripening period and improving flavor. Optimum temperature for cell growth and caseinolysis was $30^{\circ}C$ and $37{\circ}C$, respectively, and optimum pH was 7.0. The enzyme remained stable up to $50^{\circ}C$. Hydrolysis patterns of casein were also observed on SDS-PAGE. Both ${\alpha}-casein$ and ${\beta}-casein$ were totally hydrolysed by enzymes from Micrococcus sp. LL3 during culture. A preferential attack on ${\beta}-casein$ was observed. Production of aminopeptidase which cleaved polypeptides was the highest in early stationary phase during cell growth.

• Journal of Wetlands Research
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• v.7 no.2
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• pp.37-52
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• 2005

Vertical distribution of bacterial population and activities were compared between the muddy and sandy sediment of the tidal flat located in southern area of Ganghwa Island. The average of bacterial number and activities in mud flat was slightly higher than that in sand flat. Bacterial number was markedly increased at the sandflat during the investigation period, which seemed to be the result of increase of mud content. The number and activities of microorganisms in mudflat was comparable to that of the mangrove sediments. There was no differences in bacterial number with the depth, but the aminopeptidase activity and bacterial productivity were decreased markedly within 3~5cm depth of sediment due to the availability of carbon sources and molecular oxygen in pore water. The number and activities of microorganisms in mudflat did not correlated with the distribution of benthic microalgae; however, those in sand flat were closely correlated with the distribution of benthic microalgae. The distribution of marsh plant in the mudflat area might be the reason of the difference.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2303-2309
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• 2007

Expressed protein ligation (EPL) technique, joining recombinantly expressed proteins to polypeptides, has been widely adopted for addressing various biological questions and for drug discovery. However, joining two recombinant proteins together is sometimes difficult when proteins are expressed insoluble and unrefoldable, because ligation-active proteins via intein-fusion are obtainable when they are folded correctly. We overcame this limitation coexpressing target protein with additional methionine aminopeptidase (MAP) which enhances removal of the initiation methionine of recombinantly expressed protein. Our approach demonstrated that two domains of 46 kDa 5-Enolpyruvylshikimate-3-phosphate (EPSP) synthase, a target of herbicide glyphosate, were successfully joined by native chemical ligation, although its C-terminal domain was expressed as an inclusion body. The intein-fused N-terminal fragment of EPSP synthase (EPSPSN, residues 1-237) was expressed and the ligation-active thioester tagged N-terminal fragment (EPSPSN-thioester) was purified using a chitin affinity chromatography and mercapto-ethanesulphonate (MESNA) as intein thiolysis reagent. Its Cterminal fragment (EPSPSC, residues Met237-238CYS-427), expressed as an inclusion body, was prepared from an additional MAP-expressing strain. Protein ligation was initiated by mixing ~1 mM of EPSPSN-thioester with ~2 mM of EPSPSCCYS (residues 238CYS-427). Also we found that addition of 2% thiophenol increased the ligation efficiency via thiol exchange. The ligation efficiency was ~85%. The ligated full-length EPSP synthase was dissolved in 6 M GdHCl and refolded. Circular dichroism (CD) and enzyme activity assay of the purified protein showed that the ligated enzyme has distinct secondary structure and ~115% specific activity compared to those of wild-type EPSP synthase. This work demonstrates rare example of EPL between two recombinantly expressed proteins and also provides hands-on protein engineering protocol for large proteins.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.93-98
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• 1993

To investigate the organic matter transformation in aquatic environment, seasonal fluctuations of heterotrophic activity and microbia] extracellular enzyme activity were studied in Paldang Lake, Korea. The turnover time in the water column and the sediment at the station I fluctuated between 3 -I ,300 hrs and 17-170 hrs for glucose, 5 -1.900 hrs and 15-240 hrs for protein hydrolysate and 4-350 hrs and 15-230 hrs for acetic acid, respectively, indicating that the seasonal turnover time of organic substrates fluctuated drastically. The respiration ratios of glucose. protein hydrolysate and acetate were 23-32%, 38-41% and 22-28% in the water column and 34%, 61% and 41% in the sediment. respectively. These results showed that the respiration ratios in the sediment were higher than those in the water column regardless of kinds of organic substrates. The bacterial extracellular enzyme activities of $\alpha$-glucosidase. $\beta$-glucosidase, N-acetyl-$\beta$-D-glucosaminidase and aminopeptidase were 32-44%. 31-32%, 18-34% and 61-67% in the water column, and 34%. 40%, 23% and 65% in the sediment. respectively.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.251-261
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• 2017

Initially, we screened 18 Aspergillus sojae-like strains from Aspergillus spp. isolated from meju (Korean traditional fermented soybean brick) according to their morphological characteristics. Because members of Aspergillus section Flavi are often incorrectly identified because of their phylogenetic similarity, we re-identified these strains at the morphological and molecular genetic levels. Fourteen strains were finally identified as A. sojae. The isolates produced protease and ${\alpha}-amylase$ with ranges of 2.66-10.64 and 21.53-106.73 unit/g-initial dry substrate (U/g-IDS), respectively, which were equivalent to those of the koji (starter mold) strains employed to produce Japanese soy sauce. Among the isolates and Japanese koji strains, strains SMF 127 and SMF 131 had the highest leucine aminopeptidase (LAP) activities at 6.00 and 6.06 U/g-IDS, respectively. LAP plays an important role in flavor development because of the production of low-molecular-weight peptides that affect the taste and decrease bitterness. SMF 127 and SMF 131 appeared to be non-aflatoxigenic because of a termination point mutation in aflR and the lack of the polyketide synthase gene found in other A. sojae strains. In addition, SMF 127 and SMF 131 were not cyclopiazonic acid (CPA) producers because of the deletion of maoA, dmaT, and pks/nrps, which are involved in CPA biosynthesis. Therefore, A. sojae strains such as SMF 127 and SMF 131, which have high protease and LAP activities and are free of safety issues, can be considered good starters for soybean fermentations, such as in the production of the Korean fermented soybean products meju, doenjang, and ganjang.