• The Korean Journal of Mycology
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• v.14 no.3
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• pp.189-194
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• 1986

The aim of this study was to investigate physiological chracteristics of Lentinus edodes in Korea. We tried to detect properties of the several wood-degradative enzymes and investigate patterns of the enzyme production. A specific carbon source was used in the enzyme induction media for each enzymes, and the crude extract was used for the enzyme solution. With these enzyme solution, we investigated optimum temperature and pH conditions of their reactions. Moreover we investigated transition patterns of the enzyme production of the several wood-degrad­ative enzmes from Complex and Saw dust media for the purpose of studying the mechanisms of the wood component degradation by this fungus. It was assumed that the order of the wood com­ponent degradation was cellulose, xylan, and then pectic substances, and that the synergistic effects of these substances also influenced the degradation of wood components.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.83-85
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• 2019

Pseudomonas sp. PAMC 29040 was isolated from a maritime tundra soil in Antarctica for its ability to degrade lignin and subsequently confirmed to be able to depolymerize heterogeneous humic substance (HS), a main component of soil organic matter. The draft genome sequences of PAMC 29040 were analyzed to discover the putative genes for depolymerization of polymeric HS (e.g., dye-decolorizing peroxidase) and catabolic degradation of HS-derived small aromatics (e.g., vanillate O-demethylase). The information on degradative genes will be used to finally propose the HS degradation pathway(s) of soil bacteria inhabiting cold environments.

• Korean Journal of Microbiology
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• v.55 no.2
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• pp.177-179
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• 2019

Pseudomonas kribbensis CHA-19 was isolated from a temperate forest soil (mid latitude) in New Jersey, USA, for its ability to degrade humic acids, a main component of humic substances (HS), and subsequently confirmed to be able to decolorize lignin (a surrogate for HS) and catabolize lignin-derived ferulic and vanillic acids. The draft genome sequence of CHA-19 was analyzed to discover the putative genes for depolymerization of polymeric HS (e.g., dye-decolorizing peroxidases and laccase-like multicopper oxidases) and catabolic degradation of HS-derived small aromatics (e.g., vanillate O-demethylase and biphenyl 2,3-dioxygenase). The genes for degradative activity were used to propose a HS degradation pathway of soil bacteria.

• The Korean Journal of Food And Nutrition
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• v.12 no.1
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• pp.43-49
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• 1999

The effects of purine catabolites in growth media on the Serratia marcescens purine nucleoside phos-phorylase activity were examined. The enzyme activity was decreased above 60% by guanosine(5 to 15mM). The enzyme activity was not affected at low concentration of inosine (0.1∼1mM). The en-zyme activity was decreased approximately by 40∼50% in the presence of high concentrations of aden-osine hypoxanthine and xanthine (5∼15mM) but was not affected at low concentration of adenosine hypoxanthine and xanthine (0.1∼0.5mM). However the enzyme activity was increase by 20% with low concentrations of uric acid(0.5mN). but was decreased by 80% with high concentrations of same purine catabolite (15mM). Also the enxzyme activity was increased by 20% with low concentrations of glyoxylate (0.5mM) final degradative product of uric acid but was decreased by 30∼50% with high con-centrations of glyoxylate (3∼15mM). The enzyme activity was decreased approximately by 20% by the simultaneous addition of inosine hypoxanthine and uricacid at 5mM each whereas it was increased by 22 and 33% by the combination of inosine and uric acid three purine catabolites at 0.5mM respectively These data suggest that S. marcescens purine nucleoside phosphorylase is positively regulated by a glyox-ylate concentration and then may play a regulatory role in a purine catabolism.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.643-646
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• 2002

The succinic semialdehyde dehydrogenase (SSADH) inhibitory component was isolated from the EtOAc fraction of Lactuca sativa through repeated column chromatography; then, it was identified as phytol, a diterpenoid, based on the interpretation of several spectral data. Incubation of SSADH with the phytol results in a time-dependent loss of enzymatic activity, suggesting that enzyme modification is irreversible. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of $6.15{\times}10^{-2}mM^{-1}min^{-1}.$ Complete protection from inactivation was afforded by the coenzyme $NAD^{+}$, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme; therefore, it seems likely that phytol covalently binds at or near the active site of the enzyme. It is postulated that the phytol is able to elevate the neurotransmitter GABA levels in central nervous system through its inhibitory action on one of the GABA degradative enzymes, SSADH.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.480-485
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• 1996

Brain GABA transaminase is inactivated by preincubation with antidepressant/antipanic drug pheneizine (${\beta}$ethylphenylhydrazine) (mixing molar ratio 10:1) at pH 7.4. The reaction of enzyme with phenelzine was monitored by absorption and fluorescence spectroscopic methods. The inactive enzyme was fully reconstituted by addition of cofactor pyridoxal-5-phosphate. This result implies that the blocking of 1 mol of pyridoxal-5-phosphate per enzyme dimer is needed for inactivation of the enzyme. The time course of the reaction is significantly affected by the substrate .alpha.-ketoglutarate, which afforded complete protection against the loss of catalytic activity. The kinetic studies shows that phenelzine reacts with the cofactor of enzyme with a second-order rate constant of $2.1{\times}10^3M^{-1}s^{-1}$. It is postulated that the antidepressant/antipanic drug phenelzine is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on GABA degradative enzyme GABA transaminase.

• Preventive Nutrition and Food Science
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• v.2 no.4
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• pp.310-315
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• 1997

Wild propionibacteria isolated from different commercial swiss cheese samples were tested for antimicrobial activities. In initial screening, six of these Propionibacterium isolates showed antagonistic activity against 10 selected indicator organisms by the deferred method. In next, only two Propionibacterium strains JW6 and JW14 showed antibacterial activity in the cell-free supernatants by the modified well diffusion method. Propionibacterium strains JW6 and JW14 were finally identified as bacteriocin producers which exhibited a bactericidal effect against closely related species. The antimicrobial substances were proteins, since their activities were completely destroyed following several degradative enzyme treatments. The bacteriocins showed a narrow inhibitory spectrum of activity against two propionibacteria and two bacilli of strains tested in this study.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1037-1051
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• 2018

The genus Rhodococcus is a phylogenetically and catabolically diverse group that has been isolated from diverse environments, including polar and alpine regions, for its versatile ability to degrade a wide variety of natural and synthetic organic compounds. Their metabolic capacity and diversity result from their diverse catabolic genes, which are believed to be obtained through frequent recombination events mediated by large catabolic plasmids. Many rhodococci have been used commercially for the biodegradation of environmental pollutants and for the biocatalytic production of high-value chemicals from low-value materials. Recent studies of their physiology, metabolism, and genome have broadened our knowledge regarding the diverse biotechnological applications that exploit their catabolic enzymes and pathways.

• Journal of the Korean Society of Tobacco Science
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• v.13 no.2
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• pp.5-20
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• 1991

For the quality enhancement of harvested-year leaf tobacco to the quality of 2-year naturally aged leaf tobacco, cellulose and nicotine degradative bacteria were isolated and identified. Effects of artificial fermentation treated cellulase and nicotine degradative bacteria on the quality of leaf tobacco were investigated from the chemical and sensory points of view. 1, Changes in chemical composition of leaf tobacco resulted from the addition of cellulase extracted from Cellulomonas sp. [3ml(${\mu}{\textrm}{m}$ D-glucose/ml. mil-1) of enzymes solution 11009 of leaf tobacco] and nicotine degradative bacteria, Pseudomonas sp. 2ml(IX109 cells$\div$ 100g of leaf tobacco), and subsequently fermented at 40${\mu}{\textrm}{m}$$^{\circ}C$, 65% R. H. for 40 days are as follows : 1) Content of crude fiber decreased 12% It took 9 min, 53 sec. to reach full combustion in control group but took only 7 min. 47 sec. in the treated group, taking almost equal time to 2-year naturally aged leaf tobacco(7 min. 35sec.). 2) Light intensity of control group was 60.96% with bright lemon color but that of treated leaf tobacco accounted for 47.69 with orange to dark brown color series, which was almost equal to the value, 45.69, of 2-year naturally aged leaf tobacco. 3) Linoleic acid, serving mild taste among organic acids, amounted to 1.llmg/g in control group but increased to 1.35m9/9 in the treated leaf tobacco, identical to the content(1.35mg/g) of 2-year naturally aged leaf tobacco. 4) Content of solanone, on of the typical leaf tobacco flavor compounds, accounted for 2.95% in control group but increased to 2.87% in treated group. 5) Methyl furan, useful flavor compound in smoke composition, accounted for 17.6$\mu\textrm{g}$/cig. in control group but increased to 25.9$\mu\textrm{g}$/cig. in treated group. However, acroleine decreased from 69.3$\mu\textrm{g}$/cig. in control group to 58.6$\mu\textrm{g}$/cig. in treated group 2. In sonsory test, mild taste evaluation of control group scored 5.47 and treated group 7.93 which was evaluted almost equal to the value(8.00) of 2-year naturally aged leaf tobacco. Aroma evaluation of control group scored 5.60, treated group 8.20, and 2-year naturally aged leaf tobacco 8.33. In addition, total harmony taste of control group showed 5.67, treated group 8.07 (p<0.01), and 2-year naturally aged leaf tobacco 8.00. From these results, it can be said that quality of treated leaf tobacco is not inferior to that 2-year naturally aged leaf tobacco.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.9-18
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• 1996

Streptococcus mutans has been implicated as primary causative agents of dental caries by insoluble glucan (IG) in human and experimental animals. An attempt was made to search for the ${\alpha}$-1,3 glucanase that degrades IG produced by S. mutans. ${\alpha}$-1,3 glucanase was detected in the culture supernatant of microorganisms, which are isolated from soils on agar medium containing IG as a sole carbon source. This Streptomyces sp. hydrolysed IG produced by immobilized S. mutans and was named as Y9373. This enzyme required ${\alpha}$-1,3 glucan (IG) as an inducer. The optimum conditions for enzyme production were studied. The enzyme was purified by 30~70% $(NH_4)_2SO_4$ precipitation, anion exchange chroma tography on DEAE-cellulose and gel filtration on Sepadex G-75. The purified enzyme has a specific activity of 7840.0 U/mg protein giving 32.1-fold purification and final yield of 0.53%. The molecular weight was estimated to be about 22.5 kDa by SDS-PAGE. The optimum pH and temperature for enzyme reaction were 6.5 and 37$^{\circ}C$, respectively and the enzyme was relatively stable at the temperature below 60$^{\circ}C$. The activity of purified enzyme was enhanced by adding $Co^{2+},\;Mn^{2+}\;and\;Mg^{2+}$ into the medium, whereas inhibited by adding $Hg^{2+},\;Zn^{2+}$ and SDS. The $K_m\;and\;V_{max}$ value of ${\alpha}$-1,3 glucanase for IG were estimated to be 2.50 mM and 0.0431 mM/min, respectively. The thin layer chromatographic analysis of hydrolysates from IG with ${\alpha}$-1,3 glucanase showed that glucose was the main product of reaction. This enzyme activity was about 14 times higher than marketing dextranase as preventive agent against artificial dental caries by S. mutans in TH medium including 5% sucrose after 30 minutes.