• Title, Summary, Keyword: protein oxidation

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Estimation of Human Flavin-containing Monooxygenases Activity(FMO1) in the Baculovirus Expression Vector System by using S-oxidation of Methimazole

  • Kim, Young-Mi
    • Journal of Food Hygiene and Safety
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    • v.14 no.4
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    • pp.415-421
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    • 1999
  • The flavin-containing monooxygenases (FMOs) (EC 1.14. 13.8) are NADPH-dependent flavoenzymes that catalyze oxidation of soft nucleophilic heteroatom centers in a range of structurally diverse compounds including foods, drugs, pesticides, and other xenobiotics. In humans, FMOl appears to be the predominant form expressed in human fetal liver. cDNA-expressed human FMO and human liver microsomal FMO have been observed to N- and S-oxy-genate nucleophilic nitrogen- and sulfur-containing drugs and chemicals, respectively. In the present study, FMOl can be expressed in the baculovirus expression vector system at level of 2.68 nmol FMOl/mg of membrane protein. This isoform was examined for its capacity to metabolize methimazole to its S-oxide using thiocholine assay. Kinetic studies of its S-oxide by recombinant human FMO1 result in Km of 7.66 $\mu$M and Vmax of 17.79 nmol/min/mg protein.

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Modification and Inactivation of Human Ceruloplasmin by Oxidized DOPA

  • Kang, Jung-Hoon
    • Bulletin of the Korean Chemical Society
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    • v.25 no.5
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    • pp.625-628
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    • 2004
  • Ceruloplasmin (CP), the blue oxidase present in all vertebrates, is the major copper-containing protein of plasma. It has been proposed that oxidation of L-3,4-dihydroxyphenylalanine (DOPA) may contribute to the pathogenesis of neurodegenerative disorders. The effect of the oxidized products of DOPA on the modification of human CP was investigated. When CP was incubated with the oxidized L-DOPA, the protein was induced to be aggregated and ferroxidase activity was decreased in a time-dependent manner. Radical scavengers and catalase significantly inhibited the oxidized DOPA-mediated CP aggregation. Copper chelatrors, Diethylenetriaminepenta acetic acid (DTPA) and Diethyldithiocarbamic acid (DDC), also inhibited the oxidative modification of CP. The results suggested that DOPA oxidation led to the formation of free radical and induced the CP aggregation.

Diabetic Atherosclerosis and Glycation of LDL(Low Density Lipoprotein)

  • Park, Young-June;Kim, Tae-Woong
    • Preventive Nutrition and Food Science
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    • v.1 no.1
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    • pp.134-142
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    • 1996
  • Diabetes carries an increased risk of atherosclerotic disease that is not fully explained by known car-diovascular risk factors. There is accumulating evidence that advanced glycation of structural proteins, and oxidation and glycation of circulating lipoproteins, are implicated in the pathogenesis of diabetic ather-osclerosis. Reactions involving glycation and oxidation of proteins and lipids are believed to contribute to atherogenesis. Glycation, the nonenzymatic binding of glucose to protein molecules, can increase the ather-ogenic potential of certain plasma constituents, including low density lipoptotein(LDL). Glycation of LDL is significant increased in diabetic patients compared with normal subjects, even in the presence of good glycemic control. Metabolic abnormalities associated with glycation of LDL include diminished recognition of LDL by the classic LDL receptor; increased covalent binding of LDL in vessel walls ; enhanced uptake of LDL by the macrophages, thus stimulating foam cell formation ; increased platelet aggregation; formation of LDL-immune complexes ; and generation of oxygen free radicals, resulting on oxidative damage to both the lipid and protein components of LDL and to any nearby macromolecules. Oxidized lipoproteins are characterzied by cytotoxicity, potent stimulation of foam cell formation by macrophages, and procoagulant effects. Combined glycation and oxidation, "glycoxidation" occurs when oxidative reactions affect the initial products of glycation, and results in irreversible structural alterations of proteins. Glycoxidation is of greatest significance in long lived proteins such as collagen. In these proteins, glycoxidation products, believed to be atherogenic, accumulate with advancing age : in diabetes, their rate of accumulate is accelerated. Inhibition of glycation, oxidation and glycoxidation may form the basis of future antiaterogenic strategies in both diabetic and nondiabetic individuals.dividuals.

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Metabolism-Dependent Cavalent Binding of $S(-)-^3H-Nicotine$ to Lung Microsomes in Vitro

  • Kim, Bong-Hee;Shingenaga, Mark-K.
    • Archives of Pharmacal Research
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    • v.16 no.2
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    • pp.89-93
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    • 1993
  • Incubation of $S(-)-^3H$-nicotine with rabbit lung microsomes in the presence of dioxygen and NADPH results in the formation of metabolities that bind covalently to microsomal macro-molecules. The addition of cytochrome P-450 monooxygenase inhibitors, $\alpha$-methylbenzyl ami-nobenzotriazole and aroclor 1260, inhibited both (S)-nicotine metabolism and covalent binding. The relative rates of oxidation of nicotine $\Delta^{1',5'}$ iminium ion to continine indicates that lung $100,000\times{g}$ supematant catalyzed this oxidation approximately 18 times slower than that of liver system based on mg of protein, and increased covalent interactions. Since than that of liver system based on mg of protein, nd increased covalent interactions. Since the activity of lung iminium oxidase appears much lowr than the liver, it is tempting to speculate that localized concentrations of nicotine $\Delta^{1',5'}$ iminium ion in the lung will survive for a longer period of time. These results support that cytochrome P-450 catalyzed oxidation of nicotine leads to the formation of reactive nad electrophilic intemediates capable of chemical interactions with biomacromolecules.

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Oxidation-induced conformational change of Hsp33, monitored by NMR

  • Lee, Yoo-Sup;Kim, Ji-Hoon;Seo, Min-Duk;Ryu, Kyoung-Seok;Kim, Eun-Hee;Won, Hyung-Sik
    • Journal of the Korean Magnetic Resonance Society
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    • v.19 no.3
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    • pp.99-105
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    • 2015
  • Hsp33 is a prokaryotic molecular chaperon that exerts a holdase activity upon response to an oxidative stress at raised temperature. In particular, intramolecular disulfide bond formation between the four conserved cysteines that bind a zinc ion in reduced state is known to be critically associated with the redox sensing. Here we report the backbone NMR assignment results of the half-oxidized Hsp33, where only two of the four cysteines form an intramolecular disulfide bond. Almost all of the resolved peaks could be unambiguously assigned, although the total assignments extent reached just about 50%. Majority of the missing assignments could be attributed to a significant spectral collapse, largely due to the oxidation-induced unfolding of the C-terminal redox-switch domain. These results support two previous suggestions: conformational change in the first oxidation step is localized mainly in the C-terminal zinc-binding domain, and the half-oxidized form would be still inactive. However, some additional regions appeared to be potentially changed from the reduced state, which suggest that the half-oxidized conformation would be an intermediate state that is more labile to heat and/or further oxidation.

Effect of Addition of Phosvitin and High Pressure Processing on Microbiological Quality and Lipid and Protein Oxidation of Minced Chicken Leg Meat (닭 다리 분쇄육에 초고압 처리시 Phosvitin의 첨가가 미생물학적 품질과 지방 및 단백질 산화에 미치는 효과)

  • Jung, Samooel;Kang, Min-Gu;Kim, Il-Suk;Nam, Ki-Chang;Ahn, Dong-Uk;Jo, Cheo-Run
    • Food Science of Animal Resources
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    • v.32 no.2
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    • pp.212-219
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    • 2012
  • The objective of this study was to investigate the effect of high pressure (HP) processing on shelf life, as well as the addition of phosvitin on lipid and protein oxidation stability of minced chicken leg meat. Minced chicken leg meat was mixed with yolk phosvitin at 500 or 1000 mg/kg meat levels, and divided into raw and cooked groups. Then, the samples were subjected to HP at 0.1, 300, and 600 MPa. The total aerobic bacteria, lipid and protein oxidation, along with instrumental meat color ($L^*$, $a^*$, and $b^*$value) of the samples were measured during storage for 7 d at $4^{\circ}C$. In raw meat, the number of total aerobic bacteria was decreased by HP at 300 MPa (4 Log reductions) and 600 MPa (5 Log reductions) after 7 d of storage (p<0.05). HP at 600 MPa increased lipid oxidation of samples at all storage days and protein oxidation of samples during storage at 3 and 7 d. HP induced the changes of meat color by increase of $L^*$ value and decrease of $a^*$ value (p<0.05). The total aerobic bacteria was not detected in the cooked samples, regardless of HP pressure, and the lipid or protein oxidation of the cooked sample treated by 600 MPa was higher than that of the control (0.1 MPa) on day 7 or control on day 3, respectively (p<0.05). The results suggested that HP can improve the shelf life of minced chicken leg meat. However, phosvitin might be a limited antioxidative agent for the improvement of oxidation stability induced by HP.

Effect of Packaging Method on the Lipid Oxidation, Protein Oxidation, and Color in Aged Top Round from Hanwoo (Korean Native Cattle) during Refrigerated Storage

  • Kang, Sun Moon;Kang, Geunho;Seong, Pilnam;Park, Beomyoung;Cho, Soohyun
    • Food Science of Animal Resources
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    • v.34 no.3
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    • pp.273-279
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    • 2014
  • The objective of this study was to investigate the effects of the packaging method on the lipid and protein oxidation, and color in aged top round from Hanwoo (Korean native cattle) for 14 d at $4^{\circ}C$. Catalase activity was the highest (p<0.05) in vacuum packaging (VP) treatment during storage, and was higher (p<0.05) in 50% Ox-MAP and 50% Ox-MAP+vacuum skin packaging (VSP) treatments than in other treatments at d 14. Superoxide dismutase activity was higher (p<0.05) in VP, 50% Ox-MAP, and 50% Ox-MAP+VSP treatments than in other treatments at d 14. During storage, total antioxidant activity was the highest (p<0.05) in VP treatment and was higher (p<0.05) in 50% Ox-MAP+VSP treatment than in 80% Ox-MAP treatment. TBARS value was the lowest (p<0.05) in VP treatment during storage and was lower (p<0.05) in 50% Ox-MAP and Ox-MAP+VSP treatments than in 80% Ox-MAP and Ox-MAP treatments, respectively. Carbonyl content was the lowest (p<0.05) in VP treatment from 10 d. From 7 d, the $a^*$ value was the highest (p<0.05) in VP treatment and was higher (p<0.05) in 50% Ox-MAP and 50% Ox-MAP+VSP treatments than in other treatments. The $b^*$ value was the highest (p<0.05) in VP treatment from 3 d, and was higher (p<0.05) in 80% Ox-MAP+VSP, 50% Ox-MAP, and 50% Ox-MAP+ VSP treatments than in 80% Ox-MAP treatment at d 14. Therefore, VP improved the oxidation and red color stabilities in stored-aged top round compared with Ox-MAP. In addition, 50% Ox-MAP improved the lipid oxidation and red color stabilities compared with 80% Ox-MAP, and its inhibitory effect on lipid oxidation was enhanced by combination with VSP.

Storage Stability of Freeze Dried Loach for Instant Choo-o-tang (즉석 추어탕을 냉동 건조미꾸라지의 저장성)

  • 류홍수;문숙임;이수정;문갑순
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.1
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    • pp.153-160
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    • 1999
  • Storage stability of boiled and freeze dried loach and antioxidative effect of Zanthoxylum schinifolium were studied to confirm the possibility in development of instant choo o tang(Korean traditional loach soup). Packaging and storage temperature did not cause a measurable change in in vitro protein digestibility and trypsin indigestible substrate within 45 days of storage but remarkable quality changes were occurred in all samples stored after 60 days. Vacuum packaging and low temperature storage(4 oC) had some effect in retarding protein quality deterioration due to delaying polyunsaturated fatty acid oxidation. Maximum peroxide value and TBA value were reached in 15 days, and there were a slow(TBA value) and rapid reduction(POV) after peaks were reached. In contrast, increasing brown pigment development and fluorescence intensity continued until 90 days of storage. Treatment of ethanolic extracts from Zanthoxylum schinifolium prior to freeze drying could protect against lipid oxidation of freeze dried loach products.

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Purification, crystallization and X-ray crystallographic analysis of enoyl-CoA hydratase/isomerase-family protein from Cupriavidus necator H16

  • Seo, Hogyun;Kim, Kyung-Jin
    • Biodesign
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    • v.6 no.2
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    • pp.46-49
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    • 2018
  • H16_B0756 from Cupriavidus necator H16 is a putative enoyl-coenzyme A (CoA) hydratase/isomerase-family protein. Enoyl-CoA hydratase (ECH) in ${\beta}$-oxidation might provide hydroxyalkanoate monomers for PHA production. However, ${\beta}$-oxidation pathway and ECH family enzymes in C. necator have not been fully characterized. To identify the function of H16_B0756, the protein was overexpressed and purified to homogeneity by affinity and size-exclusion chromatography. The H16_B0756 protein was crystallized using hanging-drop vapor-diffusion method in the presence of 30% polyethylene glycol 550 monomethyl ether, 0.1 M sodium chloride and 0.1 M bicine, pH 9.0 at 295 K. X-ray diffraction data were collected to a maximum resolution of $2.0{\AA}$. The crystal belonged to space group P3, with unit cell parameters $a=b=132.94{\AA}$, c = 44.16, ${\alpha}={\beta}=90.0^{\circ}$, ${\gamma}=120.0^{\circ}$. With two molecules per asymmetric unit, the crystal volume per unit protein mass was $1.94{\AA}^3Da^{-1}$, which correspond to a solvent content of approximately 36.80%.

Evaluation of Antioxidative Activity of Agrimonia pilosa-Ledeb Leaves on Non-lipid Oxidative Damage

  • Hah, Dae-Sik;Kim, Chung-Hui;Kim, Eui-Kyung;Kim, Jong-Shu
    • Toxicological Research
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    • v.25 no.4
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    • pp.243-251
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    • 2009
  • Present study was conducted to evaluate the anti oxidative activity of the Agrimonia pilosa-Ledeb leaves on non-lipid oxidative damage. The antioxidative activity of methanolic (MeOH) extract of the Agrimonia pilosa-Ledeb leaves on non-lipid oxidation, including liposome oxidation, deoxyribose oxidation, protein oxidation, chelating activity against metal ions, scavenging activity against hydrogen peroxide, scavenging activity against hydroxyl radical and 2'-deoxyguanosine (2'-dG) oxidation were investigated. The MeOH extract of the Agrimonia pilosa-Ledeb leaves exhibited high anti oxidative activity in the liposome model system. Deoxyribose peroxidation was inhibited by the MeOH extract of the Agrimonia pilosa-Ledeb leaves and MeOH extract of the Agrimonia pilosa-Ledeb leaves provided remarkable protection against damage to deoxyribose. Protective effect of MeOH extracts of the Agrimonia pilosa-Ledeb leaves on protein damage was observed at $600{\mu}g$ level (82.05%). The MeOH extracts of the Agrimonia pilosa-Ledeb leaves at $300{\mu}g$ revealed metal binding ability (32.64%) for hydrogen peroxide. Furthermore, the oxidation of 2'-deoxyguanosine (2'-dG) to 8-hydroxy-2-deoxyguanosine (8-OH-2'dG) was inhibited by MeOH extracts of the Agrimonia pilosa-Ledeb leaves and scavenging activity for hydroxyl radical exhibited a remarkable effect. From the results in the present study on biological model systems, we concluded that MeOH extract of the Agrimonia pilosa-Ledeb leaves was effective in the protection of non-lipids against various oxidative model systems.