• BMB Reports
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• 제32권5호
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• pp.515-520
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• 1999

Incubation of two types of glutamate dehydrogenase isoproteins from bovine brain with the arginine-specific dicarbonyl reagent phenylglyoxal resulted in a biphasic loss of enzyme activity. Reaction of the glutamate dehydrogenase isoproteins with phenylglyoxal caused a rapid loss of 53~62% of the enzyme activities and modification of two residues of arginine per enzyme subunit. Prolonged incubation of the glutamate dehydrogenase isoproteins with phenylglyoxal resulted in the modification of an additional four residues of arginine per enzyme subunit without further loss of the residual activities. Partial protection against inactivation was provided by the coenzyme NADH or substrate 2-oxoglutarate. The most marked decrease in the rate of inactivation was observed by the combined addition of NADH and 2-oxoglutarate, suggesting that the first two modified arginine residues are in the vicinity of the catalytic site. However, inactivation of the glutamate dehydrogenase isoproteins by phenylglyoxal appears to be partial with approximately 40% activity remained after an extended reaction time with excess reagent, suggesting that the modified arginine residues may not be directly involved in catalysis. The lack of complete protection by substrates also suggest the possibility that the modified arginine residues are not directly involved at the active site, and the partial loss of activity by the modification of arginine residues may be due to a conformational change. There were no significant differences between the two glutamate dehydrogenase isoproteins in sensitivities to inactivation by phenylglyoxal, indicating that the microenvironmental structures of the glutamate dehydrogenase isoproteins are very similar to each other.

• 대한약리학회지
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• 제32권3호
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• pp.389-397
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• 1996

위점막은 위강내에서 생성되는 독성이 강한 활성산소종에 노출된다. Nitric oxide는 glutathione의 항상성을 유지시킴으로써 acetaminophen 유도 간독성에 대한 보호효과를 나타내었다. 본 연구는 hydrogen peroxide로 인한 위선세포 손상에 대한 nitric oxide의 작용을 규명하고자 하였다. Hydrogen peroxide는 ${\beta}-D-glucose$와 glucose oxidase의 반응에 의해 생성시켰으며, 위선세포에 L-arginine, $N^{G}-nitro-L-arginine$ methyl ester 및 $N^G-nitro-L-arginine$을 전처리 한 후, 세포외로 유리되는 지질과산화물 및 nitrite를 정량하고 세포내 glutathione 함량을 측정하였다. 결과로서, glucose/glucose oxidase를 처리한 경우 glucose oxidase 농도의존적으로 지질과산화물 생성은 증가되었으며, nitrite 유리 및 glutathione 함량은 감소되었다. NO synthase의 기질인 L-arginine 전처리시 glucose/glucose oxidase에 의한 지질과산화 및 nitrite 유리 증가와 세포내 glutathione 감소등이 방지되었다. $N^G-nitro-L-arginine$ methyl ester 및 $N^G-nitro-L-arginine$등 NO synthase 억제제들은 세포손상에 보호효과를 나타내지 않았다. 결론적으로 nitric oxide는 hydrogen peroxide로 인한 세포손상에 대한 보호효과가 없으며, 이는 지질과산화 반응 및 세포내 glutathione 고갈등을 억제시킴으로써 이루어진다고 사료된다.

• BMB Reports
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• 제46권11호
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• pp.555-560
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• 2013

Acrolein is the most reactive aldehydic product of lipid peroxidation and is found to be elevated in the brain when oxidative stress is high. The effects of acrolein on the structure and function of human Cu,Zn-superoxide dismutase (SOD) were examined. When Cu,Zn-SOD was incubated with acrolein, the covalent crosslinking of the protein was increased, and the loss of enzymatic activity was increased in a dose-dependent manner. Reactive oxygen species (ROS) scavengers and copper chelators inhibited the acrolein-mediated Cu,Zn-SOD modification and the formation of carbonyl compound. The present study shows that ROS may play a critical role in acrolein-induced Cu,Zn-SOD modification and inactivation. When Cu,Zn-SOD that has been exposed to acrolein was subsequently analyzed by amino acid analysis, serine, histidine, arginine, threonine and lysine residues were particularly sensitive. It is suggested that the modification and inactivation of Cu,Zn-SOD by acrolein could be produced by more oxidative cell environments.

• Journal of Applied Biological Chemistry
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• 제62권3호
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• pp.265-273
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• 2019

This study aimed to evaluate the anti-atherosclerotic and anti-hypertensive effects of six different plant extracts using a N(G)-nitro-L-arginine-methyl ester (L-NAME)-induced rat model of hypertension. All extracts were administered orally for six weeks. At the end of the study period blood pressure, blood flow, aortic histopathology, and hepatic endothelial nitric oxide synthase (eNOS) expression were measured. Subsequently, we also measured the levels of intracellular reactive oxygen species, nitric oxide (NO), and anti-inflammatory cytokines in vitro. Based on these screening results, we selected extracts of Cinnamomum cassia (C. cassia) and Salvia miltiorrhiza (S. miltiorrhiza) for further evaluation. C. cassia and S. miltiorrhiza extracts ameliorated hypertension and atherosclerosis in L-NAME-treated rats in a dose-dependent manner. In addition, a mixture of C. cassia and S. miltiorrhiza had an additive effect to reduce blood pressure, increase blood flow, and normalize aortic tissue. This mixture demonstrated anti-oxidative and anti-inflammatory activities in vitro. In conclusion, although further analysis of the therapeutic mechanism is required, the anti-hypertensive and anti-atherosclerotic effects of this mixture are likely mediated by increased eNOS expression, and its anti-oxidative and anti-inflammatory activities.

• Journal of Animal Science and Technology
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• 제62권4호
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• pp.460-467
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• 2020

The effects of arginine (Arg) and methionine (Met) supplementation on nutrient use in pigs were determined under hot season conditions. A total of five experimental diets including basal diet (CON) were supplemented with two types of amino acids (Arg and Met) and two different amounts of amino acids (0.2% and 0.4%). Under hot season condition, pigs fed with additional Arg were significantly higher in average daily gain (ADG) than the CON group and the ADG increased linearly (p < 0.05) with increasing Arg supplementation. But there was no significant difference with Met supplementation (p > 0.05). The apparent ileal digestibility (AID) of amino acids had no significant difference among treatments (p > 0.05), while d-reactive oxygen metabolites (d-ROMs) concentration in treatments with Arg supplementation, were significantly higher (p < 0.05) than other treatments. In conclusion, exposure of pigs to heat stress does not affect the AID of amino acid, whereas pig fed with additional Arg improved ADG and feed efficiency under heat stress condition.

• BMB Reports
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• 제54권10호
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• pp.516-521
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• 2021

Although arginase primarily participates in the last reaction of the urea cycle, we have previously demonstrated that arginase II is an important cytosolic calcium regulator through spermine production in a p32-dependent manner. Here, we demonstrated that rhaponticin (RPT) is a novel medicinal-plant arginase inhibitor and investigated its mechanism of action on Ca²⁺-dependent endothelial nitric oxide synthase (eNOS) activation. RPT was uncompetitively inhibited for both arginases I and II prepared from mouse liver and kidney. It also inhibited arginase activity in both aorta and human umbilical vein endothelial cells (HUVECs). Using both microscope and FACS analyses, RPT treatments induced increases in cytosolic Ca²⁺ levels using Fluo-4 AM as a calcium indicator. Increased cytosolic Ca²⁺ elicited the phosphorylations of both CaMKII and eNOS Ser1177 in a time-dependent manner. RPT incubations also increased intracellular L-arginine (L-Arg) levels and activated the CaMKII/AMPK/Akt/eNOS signaling cascade in HUVECs. Treatment of L-Arg and ABH, arginase inhibitor, increased intracellular Ca²⁺ concentrations and activated CaMKII-dependent eNOS activation in ECs of WT mice, but, the effects were not observed in ECs of inositol triphosphate receptor type 1 knockout (IP3R1^-/-) mice. In the aortic endothelium of WT mice, RPT also augmented nitric oxide (NO) production and attenuated reactive oxygen species (ROS) generation. In a vascular tension assay using RPT-treated aortic tissue, cumulative vasorelaxant responses to acetylcholine (Ach) were enhanced, and phenylephrine (PE)-dependent vasoconstrictive responses were retarded, although sodium nitroprusside and KCl responses were not different. In this study, we present a novel mechanism for RPT, as an arginase inhibitor, to increase cytosolic Ca²⁺ concentration in a L-Arg-dependent manner and enhance endothelial function through eNOS activation.

• Parasites, Hosts and Diseases
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• 제35권3호
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• pp.189-196
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• 1997

활성화된 대식세포에서 생산되는 NO가 질편모충에 대해 세포독성이 있는지를 관찰하고자 질소 중간산물에 영향을 주는 약제를 첨가한 후 nitrite 생산 및 세포독성에 미치는 영향을 관찰하였다. 대식세포로는 마우스(BAkBlc) 복강 대식세포와 마우스 복강 내 종양세포인 RAW264.7 세포로 LPS(lipopolysaccharide)나 $rIFN-{\gamma}$로 활성화시켜 사용하였다. 세포독성의 측정을 위해서 질편모충을 methyl-[$^3H$]-thymidine으로 표지하였고 NO의 측정은 Griess reagent를 사용하여 시행하였다. 마우스 복강 대식세포는 LPS로 활성화시켰을 때 질편모충에 대한 세포독성이 대조군에 비해 증가하였고, RAW264.7 세포는 $rIFN-{\gamma}$ 또는 $rIFN-{\gamma}$ 및 LPS로 활성화시켰을 때 대조군에 비해 세포독성 및 nitrite 생산량은 유의하게 증가하였다. LPS로 활성화시킨 마우스 복강 대식세포와 $rIFN-{\gamma}$로 활성화시킨 RAW264.7 세포에 NO 생산에 영향을 주는 NG-monomethyl-L-arginine(L-NMMA), NC-nitro-L-arginine methyl ester(NAME), arginase를 첨가하였을 때 약제 농도를 증가시킴에 따라 질편모충에 대한 세포독성과 nitrite 생산이 감소하였다. NO synthase coractor인 tetrahydrobiopterin($H_4B$)을 마우스 복강 대식세포에 넣었을 때 질편모충 에 대한 세포독성이 증가하였다. Ferrous sulfate를 두 종류의 활성화시킨 대식세포에 첨가하였을 때 질편모충에 대한 세포독성과 nitrite생산이 감소하였다. 이상의 성적을 종합하면 대식세포의 활성화에 따라 NO 생산 및 세포독성이 증가하였고. NO 생산을 저하시키는 약제들은 활성화된 복강 대식세포 및 RAW264.7 세포에 의한 질편모충에 대한 세포독성을 현저히 감소시키는 것으로 보아 NO는 질편모충에 대한 대식세포의 숙주 방어기전에서 중요한 역할을 감당할 것으로 생각된다.

• BMB Reports
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• 제45권3호
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• pp.147-152
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• 2012

Methylglyoxal (MG) was identified as an intermediate in non-enzymatic glycation and increased levels were reported in patients with diabetes. In this study, we evaluated the effects of MG on the modification of ferritin. When ferritin was incubated with MG, covalent crosslinking of the protein increased in a time- and MG dose-dependent manner. Reactive oxygen species (ROS) scavengers, $N-acetyl-_L-cysteine$ and thiourea suppressed the MG-mediated ferritin modification. The formation of dityrosine was observed in MG-mediated ferritin aggregates and ROS scavengers inhibited the formation of dityrosine. During the reaction between ferritin and MG, the generation of ROS was increased as a function of incubation time. These results suggest that ROS may play a role in the modification of ferritin by MG. The reaction between ferritin and MG led to the release of iron ions from the protein. Ferritin exposure to MG resulted in a loss of arginine, histidine and lysine residues. It was assumed that oxidative damage to ferritin caused by MG may induce an increase in the iron content in cells, which is deleterious to cells. This mechanism, in part, may provide an explanation or the deterioration of organs under diabetic conditions.

• Food Science and Biotechnology
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• 제17권1호
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• pp.95-101
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• 2008

Some biological activities of Beauveria bassiana were studied to elucidate pharmacological function of B. bassiana-infected larva of the silkworm. The mycelium consisted mainly of carbohydrate (65.8%), followed by protein (15.9%) and fat (8.3%). Glucose (68.8%), mannose (7.1%), and galactose (6.1%) were major components in carbohydrates. Ten amino acids including glutamine, threonine, valine, aspartic acid, alanine, leucine, serine, glycine, arginine, and isoleucine were found in protein as major amino acids. Various extracts were prepared from the freeze-dried mycelium of B. bassiana by systemic extraction and their biological activities were investigated. Among tested fractions, the hot-water extract (HW) contributed significantly to the anti-coagulant activity, anti-complementary activity, and stimulation of intestinal immune system. The methanol extract (ME) increased acetylcholinesterase (AChE) inhibition activity and reactive oxygen species (ROS) scavenging activity.

• Animal cells and systems
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• 제4권2호
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• pp.151-155
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• 2000

Nitric oxide (NO) is a reactive free radical which plays important roles in animal physiology. To investigate involvement of NO in acrosome reaction (AR), effects of drugs which modulate the intracellular NO level were examined in mouse spermatozoa. N (G)-nitro-L-arginine (L-NA), a potent inhibitor of NO synthesis, decreased AR in a reversible manner, On the other hand, sodium nitroprusside (SNP), an NO generating agent, increased spontaneous AR. Preincubation of sperm in the presence of L-NA potentiated AR after sperm transfer into plain- or SNP-media. Methylene blue, a NO scavenging agent, decreased spontaneous AR. Taken together, it is concluded that NO positively controls AR.