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양성렬,최기오,박종근,류문희,홍석노,김수한,안봉환,이제혁,이민화 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.4
Protective effects of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr< -10,000) fraction of CSF inactivated the exogenous GS, but large-molecular(Mr> -10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT) was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatogrpahy, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu^(2+)-induced GS inactivation in the presence of DTT. Uric acid and glucose did not show any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and that transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.
Comparative Proteomic Analysis of Cysteine Oxidation in Colorectal Cancer Patients
양희영,이태훈,Kee Oh Chay,권요셉,권상오,박영규 한국분자세포생물학회 2013 Molecules and cells Vol.35 No.6
Oxidative stress promotes damage to cellular proteins, lipids, membranes and DNA, and plays a key role in the development of cancer. Reactive oxygen species disrupt redox homeostasis and promote tumor formation by initiating aberrant activation of signaling pathways that lead to tumorigenesis. We used shotgun proteomics to identify proteins containing oxidation-sensitive cysteines in tissue specimens from colorectal cancer patients. We then compared the patterns of cysteine oxidation in the membrane fractions between the tumor and non-tumor tissues. Using nano-UPLC-MSE proteomics, we identified 31 proteins con-taining 37 oxidation-sensitive cysteines. These proteins were ob-served with IAM-binding cysteines in non-tumoral region more than tumoral region of CRC patients. Then using the Ingenuity pathway program, we evaluated the cellular canonical networks connecting those proteins. Within the networks, proteins with multiple connections were related with organ morphology, cellular metabolism, and various disorders. We have thus identified networks of proteins whose redox status is altered by oxidative stress, perhaps leading to changes in cellular functionality that promotes tumorigenesis.
송동업,Hyun Joong Yoon,Kee-Oh Chay,주영은,정영도,안봉환,Mi Sun Jang,Hyun Woo Kim,양성렬 전남대학교 의과학연구소 2014 전남의대학술지 Vol.50 No.1
This study was designed to evaluate the efficacy of an orally administered aqueous extractof glutinous rice (GRE) to protect against acute gastric mucosal lesions inducedby ethanol, indomethacin, and water immersion restraint stress in rats and to characterizethe active substances responsible for the protection. GRE was shown to dose-dependentlyprevent the gastric lesions induced by the above ulcerogenic treatments atdoses of 30 to 300 mg/kg. GRE treatment increased the gastric mucin content and partiallyblocked the ethanol-induced depletion of the gastric mucus layer. Also, it increasedthe nonprotein sulfhydryl concentration in the gastric mucosa. The gastroprotectiveaction of GRE was markedly enhanced by co-treatment with 4-8 mg/kg tea extracts. The activity of GRE was completely lost by heat treatment at 80oC for 3 min or treatmentwith 0.01% pepsin at 37oC for 1 h. Protein extraction studies indicated that prolaminsare involved in the gastroprotective activity of GRE. Our results suggest that glutinousrice proteins are useful for the prevention and treatment of gastritis and peptic ulcer.
Comparative proteomic analysis of cysteine oxidation in colorectal cancer patients
Yang, Hee-Young,Chay, Kee-Oh,Kwon, Joseph,Kwon, Sang-Oh,Park, Young-Kyu,Lee, Tae-Hoon Springer-Verlag 2013 Molecules and cells Vol.35 No.6
<P>Oxidative stress promotes damage to cellular proteins, lipids, membranes and DNA, and plays a key role in the development of cancer. Reactive oxygen species disrupt redox homeostasis and promote tumor formation by initiating aberrant activation of signaling pathways that lead to tumorigenesis. We used shotgun proteomics to identify proteins containing oxidation-sensitive cysteines in tissue specimens from colorectal cancer patients. We then compared the patterns of cysteine oxidation in the membrane fractions between the tumor and non-tumor tissues. Using nano-UPLC-MSE proteomics, we identified 31 proteins containing 37 oxidation-sensitive cysteines. These proteins were observed with IAM-binding cysteines in non-tumoral region more than tumoral region of CRC patients. Then using the Ingenuity pathway program, we evaluated the cellular canonical networks connecting those proteins. Within the networks, proteins with multiple connections were related with organ morphology, cellular metabolism, and various disorders. We have thus identified networks of proteins whose redox status is altered by oxidative stress, perhaps leading to changes in cellular functionality that promotes tumorigenesis.</P>
Noh, Eun-Mi,Lee, Young-Rae,Chay, Kee-Oh,Chung, Eun-Yong,Jung, Sung Hoo,Kim, Jong-Suk,Youn, Hyun Jo D. A. Spandidos 2011 MOLECULAR MEDICINE REPORTS Vol.4 No.2
<P>Estrogen receptor α (ERα) mediates most of the biological effects of estrogen in mammary epithelial cells and stimulates growth signals involving phosphoinositide-3-OH kinase (PI3K)/Akt in breast cancer cells. Phosphatase and tensin homologue (PTEN) is a critical counter-regulator of PI3K signaling and is thus one of the major tumor suppressors in breast cancer. Inhibition of PI3K with an inhibitor, wortmannin, increased the level of PTEN protein in ERα-positive MCF-7 cells, while levels in ERα-negative MDA-MB 231 cells were not altered. In addition, the level of PTEN protein in MCF-7 cells was significantly lower than that in MDA-MB 231 cells, which correlated with high levels of phospho-Akt and phosphatidylinositol-3,4,5,-trisphosphate (PIP3). However, PTEN mRNA expression as measured by real-time PCR showed no differences in either cell line. Notably, the levels of casein kinase 2 (CK2) and phospho-PTEN (Ser380/Thr382/383) in MCF-7 cells were lower than those in MDA-MB 231 cells, indicating that the down-regulation of PTEN protein in MCF-7 cells is caused by low levels of CK2 expression, leading to accelerated PTEN degradation. Collectively, these results suggest that ERα induces the down-regulation of PTEN through PI3K activation in breast cancer cells.</P>