• Journal of Life Science
• /
• v.8 no.4
• /
• pp.416-420
• /
• 1998

Soybean sprouts peroxidase can be used for enzymatic determination of glucose. Peroxidase from soybean sprouts was purified by ammonium sulfate precipitation and DEAE Sephacel column chromatography. The glucose could be quantitatively assayed by using glucose oxidase and soybean sprouts peroxidase. The optimum pH and temperature for glucose assay were of pH 5.5 and $40^{\circ}C$, respectively. The relationship between absorbance and glucose concentration was linear. And also the relationship between absorbance and reaction time was linear. The reducing agents such as L-cysteine, dithiothreitol inhibited the glucose assay by glucose oxidase and soybean sprouts peroxidase.

• YAKHAK HOEJI
• /
• v.49 no.4
• /
• pp.330-334
• /
• 2005

Antimutagenic activity of the enzymatic browning reaction products (EBRPs) was investigated by using the spore rec-assay with Bacillus subtilis strains H17 $(rec^+)\;and\;M45 (rec^-)$. The EBRPs tested were prepared from the reactions of five different kinds of polyphenols with polyphenol oxidase isolated from the leaves Perilla frutescens. In the spore rec-assay, most of the polyphenolic compounds tested showed positive, whereas only their tested compound showed negative respectively. In addition of polyphenol oxidase inhibitors such as cysteine, glutathione and ascorbic acid to the reaction mixtures consisted with the polyphenol oxidase and polyphenols, the mutagenic effects were increased in the spore recassay. These results show that the activity of polyphenol oxidase may play an important role in the reduction of mutagenicity of polyphenols.

• The Journal of Korean Medicine
• /
• v.17 no.2 s.32
• /
• pp.191-202
• /
• 1996

Cervus elaphus for herb-acupuncture solution(CEHAS) was tested for the effects of free radical generating enzyme and lipid peroxidation in rat's liver. In vitro, levels of lipid peroxide in tissues of liver were proportionally decreased to concentration of CEHAS. They were much more decreased. when lipid peroxidation was induced with ferrous iron $(Fe^{-2})$. Also, enzyme activities of xanthine oxidase were decreased. The ratio of type conversion of xanthine oxidase was lowered, too. But, here was not special changes on enzyme activities of aldehyde oxidase. These results suggest that CEHAS decrease the activities of free radical generating enzymes such as xanthine oxidase which form lipid peroxide.

• BMB Reports
• /
• v.37 no.6
• /
• pp.753-756
• /
• 2004

Membranes prepared from Bacillus cereus KCTC 3674, grown aerobically on a complex medium, oxidized NADH exclusively, whereas deamino-NADH was little oxidized. The respiratory chain-linked NADH oxidase exhibited an apparent $K_m$ value of approximately $65\;{\mu}m$ for NADH. The maximum activity of the NADH oxidase was obtained at about pH 8.5 in the presence of 0.1 M KCl (or NaCl). Respiratory chain inhibitor 2-heptyl-4-hydroxyquinoline-N-oxide (HQNO) inhibited the activity of the NADH oxidase by about 90% at a concentration of $40\;{\mu}m$. Interestingly, rotenone and capsaicin inhibited the activity of the NADH oxidase by about 60% at a concentration of $40\;{\mu}m$ and the activity was also highly sensitive to $Ag^+$.

• Korean Journal of Oriental Medicine
• /
• v.2 no.1
• /
• pp.192-204
• /
• 1996

Cervus elaphus for herb-acupuncture solution (CEHAS) was tested for the effects of free radical generating enzyme and lipid peroxidation in rat's kidney. In vitro, levels of lipid peroxide in tissues of kidney were proportionally decreased to concentration of extracts prepared from CEHAS. They were much more decreased, when lipid peroxidation was induced with ferrous iron (FeII). Also, enzyme activities of xinthine oxidase were decreased. The ratio of type conversion of xanthine oxidase was lowered, two. But, it was not seen changes on enzyme activities of aldehyde oxidase. These results suggest that CEHAS decrease the activities of free radical generating enzymes such as xanthine oxidase which form lipid peroxide.

• Microbiology and Biotechnology Letters
• /
• v.15 no.6
• /
• pp.402-407
• /
• 1987

Glucose oxidase from Aspergillus niger KUF-04 was purified homogeneously by the procedure of seven steps including crystallization. The ball-like crystalline enzyme was obtained from the 23-fold purified enzyme solution. The glucose oxidase was found to be composed of two identical subunits and the molecular weight of the enzyme and its subunit were estimated to be about 210, 000 and 110, 000 by HPLC and SDS-acrylamide gel electrophoresis, respectively.

• BMB Reports
• /
• v.28 no.6
• /
• pp.490-493
• /
• 1995

We investigated the effect of hydrogen peroxide-treated metallothionein on the hepatic xanthine oxidase activity in vitro. When the metallothionein was preincubated with 1 mM of hydrogen peroxide, the activity of xanthine oxidase and type conversion were elevated dose-dependently by the addition of metallothionein into the reaction mixture. While increasing the treatment of hydrogen peroxide to the $50{\mu}g$of metallothionein, the xanthine oxidase activity and type conversion ratio were remarkably elevated dose dependently compared to the control. When cadmium ion was added to the reaction mixture, the increasing pattern of the enzyme activity was similar to the effect of hydrogen peroxide-treated metallothionein. DTT or penicillamine restored the increasing activity and type conversion of xanthine oxidase by the cadmium ion to the control level.

• Korean Journal of Microbiology
• /
• v.26 no.1
• /
• pp.44-51
• /
• 1988

The intracellular free radicals produced at different stages of cell cycle of Saccharomyces cerevisiae ATCC 24858 were investigated by means of electron spin resonance(ESR) spectroscopy. The synchronized cells by repeated starvation and refeeding revealed different ESR spectral pattern compared to that of asynchronized cells. Each spectrum centered at g=2.005, which indicates free radicals. The relative spin concentration was maximat at the end of DNA increase. The variation of the relative spin concentration at each distinct stage of the cell cycle was evaluated in relation to ascorbate concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. The highest activities of L-galactonolactone oxidase and ascorbate oxidase were detected just before and at the maximum of relative spin concentration, respectively. And ascorbate concentration fluctuated through each stage of cell cycle with the changes of relative spin concentration, L-galactonolactone oxidase activity, and ascorbate oxidase activity. Thus it is suggested that intracellular free radicals should be related to cell cycle, interacted with ascorbate, and may play an important role in the cell cycle of Saccharomyces cerevisiae.

• Applied Biological Chemistry
• /
• v.30 no.3
• /
• pp.278-284
• /
• 1987

As a basic research for inhibition of enzymatic browning of apples during dehydration or processing, polyphenol oxidase was extracted from Fuji apples to investigate heat inactivation, chemical inhibition and other properties. Polyphenol oxidase showed the highest activity at $20^{\circ}C$ and pH 5.5 with catechol as substrate, and the Michaelis constant of 0.14 M under the same condition of substrate and pH. The thermal inactivation followed pseudo first-order kinetics to have activation energy of 23.0 kcal/mol and z value of $19.7^{\circ}C$. As for substrate specificity the polyphenol oxidase showed high affinity toward the o-diphenolic compounds, particularly chlorogenic acid. Neither the m- and p-dihydroxy phenols nor monophenols were attacked. Browning by polyphenol oxidase was completely inhibited at the concentrations of 10mM for potassiummetasulfite and thiourea and 1mM for L-cysteine, ascorbic acid and sodium diethyldithiocarbamate.

• The Korean Journal of Pharmacology
• /
• v.23 no.1
• /
• pp.33-44
• /
• 1987

NADPH oxidase dependent superoxide generation and phagocytosis in neutrophils stimulated with opsonized zymosan or heat aggregated IgG were coincided with the process of calcium uptake. The responses in activated neutrophils were enhanced with increasing concentrations of extracellular calcium and these effects were significantly inhibited by calcium chelators, EGTA and EDTA. The superoxide generation in activated neutrophils was reduced by dantrolene and chlorpromazine. Calcium antagonists, bepredil, diltiazem, verapamil, nifedipine and nimodipine effectively inhibited the calcium uptake, superoxide generation and phagocytosis in activated neutrophils, and NADPH oxidase activity was also inhibited. The results suggest that calcium antagonists may inhibit the superoxide generation and phagocytosis in activted neurtophils by the inhibition of calcium influx and by the action on intracellular redistribution of calcium and NADPH oxidase system.