Xanthine oxidase 활성 및 형전환에 미치는 구리이온의 영향

허근,이상일,박진우 영남대학교 약품개발연구소 1994 영남대학교 약품개발연구소 연구업적집 Vol.4 No.-

Copper intoxication and disturbance of copper metabolism induced various oxygen-derived free radicals related damages. The effect of copper ion on xanthine oxidase activity and type conversion of the enzyme which is concerned to generation of reactive oxygen species, was investigated. It was observed that xanthine oxidase activity was increased by addition of copper ion in the reaction mixture in proportional to the concentration of the metal ion until 60 μM, while the enzyme activity was inhibited in higher concentration of copper treatment. On the other hand, xanthine dehydrogenase activity was inhibited by copper ion addition with concentration dependently. Preincubation of enzyme source with 30 μM of copper ion, which concentration marked increased the xanthine oxidase activity, unchanged the enzyme activity and type conversion compare to control in vitro system. It was also observed that copper induced xanthine oxidase activity and the enzyme type conversion was protected by dithiothreitol and penicillamine. These results indicate that the increment of the type conversion of xanthine oxidase necessarilly need the presence of copper ion in enzyme assay system.

Antagonists of Phosphatidylinositol 3-Kinase Block Phosphorylation-Dependent Activation of the Leukocyte NADPH Oxidase in a Cell-Free System

Park, Jeen-Woo Korean Society for Biochemistry and Molecular Biol 1997 Journal of biochemistry and molecular biology Vol.30 No.3

The NADPH oxidase of phagocytes catalyzes the reduction of oxygen to $O_2^-$ at the expense of NADPH. The enzyme is dormant in resting neutrophils and becomes activated on stimulation. During activation, $p47^{phox}\;(\underline{ph}agocyte\;\underline{ox}idase\;factor)$, a cytosolic oxidase subunit, becomes extensively phosphorylated at a number of serines located between S303-S379. Oxidase activation can also be achieved by the addition of phosphorylated recombinant $p47^{phox}$ by protein kinase C in the cell-free system in the presence of $GTP{\gamma}S$. The cell-free activation is inhibited by wortmannin and LY294002. specific inhibitors of phosphatidylinositol 3kinase (PI 3-kinasel) These results indicate that PI 3-kinase may playa pivotal role in the activation of NADPH oxidase.

Change in the Conformation of $p47^{phox}$ by Sodium Dodecyl Sulfate, an Activator of the Leukocyte NADPH Oxidase

Park, Jeen-Woo,Park, Hee-Sae Korean Society for Biochemistry and Molecular Biol 1998 Journal of biochemistry and molecular biology Vol.31 No.3

The leukocyte NADPH oxidase of neutrophils is a membrane-bound enzyme that catalyzes the production of $O_2^-$ from oxygen using NADPH as an electron donor. Dormant in resting neutrophils, the enzyme acquires catalytic activity when the cells are exposed to appropriate stimuli. During activation, the cytosolic oxidase components $p47^{phox}$ and $p67^{phox}$ migrate to the plasma membrane, where they associate with cytochrome $b_{558}$, a membrane-bound flavohemoprotein, to assemble the active oxidase. The oxidase can be activated in a cell-free system; the activating agent usually employed is an anionic amphiphile such as sodium dodecyl sulfate (SDS). Because $p47^{phox}$ can translocate by itself during activation, the conformational change in $p47^{phox}$ may be responsible for the activation of NADPH oxidase. We show here that the treatment of $p47^{phox}$ with SDS leads to an increase in the reactivity of the sutbydryl group of cysteines toward N-ethylmaleimide, indicating that the conformational change occurs when $p47^{phox}$ is exposed to SDS. We propose that this change in conformation results in the appearance of a binding site through which $p47^{phox}$ interacts with cytochrome $b_{558}$during the activation process.

Direct analysis of nicotelline from tobacco by MS with DADI/MIKE spectrometry

Park, Jeen-Woo The Pharmaceutical Society of Korea 1982 Archives of Pharmacal Research Vol.5 No.1

Nicotelline was directly analyzed from the crude tobacco extract by metastable studies. The metastable transitions of nicotelline were investigated by MS with DADI/MIKE spectrometry.

Symposia special lectures : Respiratory Burst Oxidase : Existence of Cytosolic Components as a Complex and the Regulation of Activation

Jeen Woo Park,Bernard M . Babior 생화학분자생물학회(구 한국생화학분자생물학회) 1992 추계학술대회집 Vol.- No.-

Oxidative Damage to DNA and Modulation of Antioxidant Enzymes During Ischemia/Reperfusion Insult to Gerbil Brain

Park, Jeen-Woo,An, Soo Mi,Lee, Mi Hye,Kim, Kang Hwa,Kim, Il Han,Huh, Keun 영남대학교 약품개발연구소 1994 영남대학교 약품개발연구소 연구업적집 Vol.4 No.-

It has been proposed that oxygen-derived free radicals are produced upon reperfusion of ischemic brain, and that they can cause tissue injury to the brain. Global ischemia/reperfusion insult to gerbil brain was produced by transient occulsion and release of both common carotid arteries. Oxidative DNA damge, as measured by the 8-hydroxy-2'-deoxyguanosine (8-OH-dG) level, was increased by ischemia/reperfusion insult. Ichemia/reperfusion insult to gerbil brain did not cause any significant induction of antioxidant enzymes, such as superoxide dismutase, catalase, or a thiol-dependent protector protein. However, catalase activity was slightly decreased. These results suggest that ischemia/reperfusion insult to gerbil brain causes the DNA damage via the production of reactive oxygen species and that the antioxidant enzyme systems were not induced to prevent oxidative damage to DNA.

Change in the Conformation of P47phox by Sodium Dodecyl Sulfate, an Activator of the Leukocyte NADPH Oxidase

Park, Jeen-Woo,Park, Hee-Sae The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.3

The leukocyte NADPH oxidase of neutrophilis is a membrane-bound enzyme that catalyzes the production of O₂-from oxygen using NADPH as an electron donor. Dormant in resting neutrophils, the enzyme acquires catalytic activity when the cells are exposed to appropriate stimuli. During activation, the cytosolic oxidase components p47phox and p67phox migrate to the plasma membrane-bound flavohemoprotein, to assemble the active oxidase. The oxidase can be activated in a cell-free system; the activating agent usually employed is an anionic amphiphile such as sodium dodecyl sulfate (SDS). Because p47phox can translocate by itself during activation, the conformational change in p47phox may be responsible for teh activation of NADPH oxidase. We show here that the treatment of p47phox with SDS leads to an increase in the reactivity of the sufhydryl group of cysteines toward N-ethylmaleimide, indicating that the conformational change occurs when p47phox is exposed to SDS. We propose that this change in conformation results in the appearance of a binding site through which p47phox interacts with cytochrome b558 during the activation process.

Protective Role of Thioredoxin Peroxidase Against Ionizing Radiation

Park, Jeen-Woo,Lee, Su Min,Kim, Sun Yee The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.6

A soluble protein from Saccharomyces cerevisiae provides protection against a thiol-containing oxidation system but not against an oxidation system without thiol. This 25-kDa protein acts as a peroxidase but requires the NADPH-dependent thioredoxin system or a thiol-containing intermediate, and was thus named thioredoxin peroxidase. The protective role of thioredoxin peroxidase against ionizing radiation, which generates reactive oxygen species harmful to cellular function, was investigated in wild-type and mutant yeast strains in which the tsa gene encoding thioredoxin peroxidase was disrupted by homologous recombination. Upon exposure to ionizing radiation, there was a distinct difference between these two strains in regard to viability and the level of protein carbonyl content, which is the indicative marker of oxidative damage to protein. Activities of other antioxidant enzymes, such as catalase, superoxide dismutase, glucose-6-phosphate dehydrogenase, and glutathione reductase were increased at 200-600 Gy of irradiation in wild-type cells. However, the activities of antioxidant enzymes were not significantly changed by ionizing radiation in thioredoxin peroxidase-deficient mutant cells. These results suggest that thioredoxin peroxidase acts as an antioxidant enzyme in cellular defense against ionizing radiation through the removal of reactive oxygen species as well as in the protection of antioxidant enzymes.

Regulation of redox status and apoptosis by NADP^(+)-dependent isocitrate dehydrogenase

Park, Jeen-Woo 이화여자대학교 세포신호전달연구센터 2009 고사리 세포신호전달 심포지움 Vol. No.11

Recently, we demonstrated that the control of redox balance and the cellular defense against oxidative damage is one of the primary functions of NADP^(+)-dependent isocitrate dehydrogenases(ICDHs). We demonstrate that modulation of IDPm activity in U937 cells, regulates ionizing radiation-induced apoptosis. When we examined the regulatory role of IDPm against ionizing radiation-induced apoptosis in U937 cells transfected with the cDNA for mouse IDPm in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPm expressed in target cells and their susceptibility to apoptosis. Upon exposure to 2 Gy of γ-irradiation, there was a distinct difference between the IDPm transfectant cells in regard to morphological evidence of apoptosis, DNA fragmentation, cellular redox status, oxidative damage to cells, mitochondria function, and the modulation of apoptotic marker proteins. In addition, transfection of HeLa cells with an IDPm small interfering RNA(siRNA) decreased activity of IDPm, enhancing the susceptibility of radiation-induced apoptosis. Taken together, these results indicate that IDPm may play an important role in regulating the apoptosis induced by ionizing radiation and the effect of IDPm siRNA on HeLa cells offers the possibility of developing a modifier of radiation therapy. We also demonstrate that silencing of IDPm expression in HeLa cells greatly enhances apoptosis induced by TNF-α and anticancer drugs. Transfection of HeLa cells with an IDPm siRNA markedly decreased activity of IDPm, enhancing the susceptibility of anticancer agent-induced apoptosis reflected by morphological evidence of apoptosis, DNA fragmentation, cellular redox status, mitochondria redox status and function, and the modulation of apoptotic marker proteins. These results indicate that IDPm may play an important role in regulating the apoptosis induced by TNF-α and anticancer drugs and the sensitizing effect of IDPm siRNA on the apoptotic cell death of HeLa cells offers the possibility of developing a modifier of cancer chemotherapy.

hCG-induced endoplasmic reticulum stress triggers apoptosis and reduces steroidogenic enzyme expression through activating transcription factor 6 in Leydig cells of the testis

Park, Sun-Ji,Kim, Tae-Shin,Park, Choon-Keun,Lee, Sang-Hee,Kim, Jin-Man,Lee, Kyu-Sun,Lee, In-kyu,Park, Jeen-Woo,Lawson, Mark A,Lee, Dong-Seok Society for Endocrinology 2013 Journal of molecular endocrinology Vol.50 No.2

<P>Endoplasmic reticulum (ER) stress generally occurs in secretory cell types. It has been reported that Leydig cells, which produce testosterone in response to human chorionic gonadotropin (hCG), express key steroidogenic enzymes for the regulation of testosterone synthesis. In this study, we analyzed whether hCG induces ER stress via three unfolded protein response (UPR) pathways in mouse Leydig tumor (mLTC-1) cells and the testis. Treatment with hCG induced ER stress in mLTC-1 cells via the ATF6, IRE1a/XBP1, and eIF2α/GADD34/ATF4 UPR pathways, and transient expression of 50 kDa protein activating transcription factor 6 (p50ATF6) reduced the expression level of steroidogenic 3β-hydroxysteroid dehydrogenase △5-△4-isomerase (3β-HSD) enzyme. In an <I>in vivo</I> model, high-level hCG treatment induced expression of p50ATF6 while that of steroidogenic enzymes, especially 3β-HSD, 17α-hydroxylase/C17–20 lyase (CYP17), and 17β-hydrozysteroid dehydrogenase (17β-HSD), was reduced. Expression levels of steroidogenic enzymes were restored by the ER stress inhibitor tauroursodeoxycholic acid (TUDCA). Furthermore, lentivirus-mediated transient expression of p50ATF6 reduced the expression level of 3β-HSD in the testis. Protein expression levels of phospho-JNK, CHOP, and cleaved caspases-12 and -3 as markers of ER stress-mediated apoptosis markedly increased in response to high-level hCG treatment in mLTC-1 cells and the testis. Based on transmission electron microscopy and H&E staining of the testis, it was shown that abnormal ER morphology and destruction of testicular histology induced by high-level hCG treatment were reversed by the addition of TUDCA. These findings suggest that hCG-induced ER stress plays important roles in steroidogenic enzyme expression via modulation of the ATF6 pathway as well as ER stress-mediated apoptosis in Leydig cells.</P>