• 한국미생물·생명공학회지
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• 제25권4호
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• pp.374-378
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• 1997

Glutathione S-transferase (GST) was purified from Pseudomonas sp. DJ77, and its N-terminal sequence was determined to be MKLFISPGACSL. A specific tyrosyl residue in the vicinity of the N terminus is conserved in all the known cytosolic GSTs and has been shown to function as a catalytic residue in $\alpha$, $\mu$, $\pi$ class GSTs from mammals. However, Pseudomonas sp. DJ77 GST has the Phe-4 and Ile-5 instead of Tyr in N-terminus. Its replacement with tyrosine did not significantly affect the enzyme activity. Results from in vitro biochemical analyses were confirmed by the in vivo activity-based CDNB growth inhibition analyses. Our results clearly indicate that GST of Pseudomonas sp. DJ77 has a novel reaction mechanism different from that of mammalian GSTs.

• Journal of Applied Biological Chemistry
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• 제60권2호
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• pp.133-136
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• 2017

Fermentation plays a vital role in the nutritional enrichment of food. Korea has a long tradition of adding fermented food to the daily diet and jeotgal is one of the common fermented and salted foods in Korean cuisine. In our study, we added soymilk as an additive to squid jeotgal to improve its functionality. We mixed different concentrations of soymilk (2, 5, and 10 mg/g) with squid jeotgal samples, fermented them for one week, and then tested their antioxidant and anticancer activities to compare with those of squid jeotgal samples without soymilk additive. To investigate the anticancer characteristics, glutathione-S-transferase (GST)-pi enzyme assay was used. To test the antioxidant activities, various assays were performed, including 2,2-diphenyl-1-picryl hydrazyl free radical scavenging activity, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium saltradical cation scavenging assay, and reducing power assay. Samples fermented with a small amount of soymilk showed excellent anticancer activity. The addition of only 2 mg/g of soymilk to squid jeotgal inhibited the activity of GST-pi by almost 50% when compared with the sample with no addition. Moreover, no undesirable bitterness or astringency was noticed. Our results could help to improve the current food status of squid jeotgal and it could be used to reduce the risk of chronic disease along with its basic nutritional function.

• 한국균학회지
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• 제30권2호
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• pp.124-130
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• 2002

본 연구에서는 버들송이(Agrocybe cylindracea)와 말똥진흙버섯(Phellinus igniarius)을 배양한 대두 추출물의 암예방 효과를 검토하기 위하여 in vitro상에서 암발생 억제물질 연구에 널리 이용되고 있는 기작 즉, Quinone reductase(QR), glutathione S-transerase(GST)의 활성 유도, glutathione(GSH)의 생성 촉진 그리고, polyamine 합성대사의 억제능을 측정하였다. 그 결과, 버들송이와 말똥진흙버섯를 배양한 대두 추출물이 마우스 hepatoma Hepa1c1c7 cell 배양에서 QR과 GST 유도활성이 있음이 확인되었다. 또한 GSH 생성량은 버들송이를 배양한 대두 추출물에서 20%, 말똥진흙버섯를 배양한 대두 추출물에서 40%로 증가하였다. 한편, 버들송이와 말똥진흙버섯을 배양한 대두 추출물의 polyamine 합성대사의 억제효과를 검토하기 위해 Acanthamoeba castellanii의 증식을 측정하였다. 그 결과, 버들송이와 말똥진흙버섯을 배양한 대두 추출물 20mg/3ml와 40mg/3ml를 처리할 경우 A. castellanii의 증식을 억제하는 것으로 나타났다. 이러한 결과 담자균을 배양한 대두 추출물은 in vitro상에서 나타난 암과 관련된 각종 활성으로부터 암예방 효과가 있는 것으로 나타나 기능성 식품으로서의 가능성을 보여주었다.

• Archives of Pharmacal Research
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• 제27권7호
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• pp.757-762
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• 2004

The protective adaptive response to electrophiles and reactive oxygen species is mediated by the induction of phase II detoxifying genes including glutathione S-transferases (GSTs). NF-E2-related factor-2 (Nrf2) phosphorylation by protein kinase C (PKC) is a critical event for its nuclear translocation in response to oxidative stress. Previously, we have shown that peroxynitrite plays a role in activation of Nrf2 and Nrf2 binding to the antioxidant response element (ARE) via the pathway of phosphatidylinositol 3-kinase (PI3-kinase) and that nitric oxide synthase in hepatocytes is required for GSTA2 induction. In view of the importance of PKC and Pl3-kinase in Nrf2-mediated GST induction, we investigated the role of these kinases in peroxynitrite formation for GSTA2 induction by oxidative stress and determined the relationship between PKC and PI3-kinase. Although PKC activation by phorbol 12-myristate-13-acetate (PMA) did not increase the extents of constitutive and inducible GSTA2 expression, either PKC depletion by PMA or PKC inhibition by staurosporine significantly inhibited GSTA2 induction by tert-butylhydroquinone (t-SHa) a prooxidant chemical. Therefore, the basal PKC activity is req- uisite for GSTA2 induction. 3-Morpholinosydnonimine (SIN-1), which decomposes and yields peroxynitrite, induced GSTA2, which was not inhibited by PKC depletion, but slightly enhanced by PKC activation, suggesting that PKC promotes peroxynitrite formation for Nrf2-mediated GSTA2 induction. Treatment of cells with S-nitroso-N-acetyl-penicillamine (SNAP), an exogenous NO donor, in combination with t-BHQ may produce peroxynitrite. GSTA2 induction by SNAP ＋ t-BHQ was not decreased by PKC depletion, but rather enhanced by PKC activation, showing that the activity of PKC might be required for peroxynitrite formation. LY294002 a P13-kinase inhibitor blocked GSTA2 induction by t-BHQ, which was reversed by PMA-induced PKC activation. These results provide evidence that PKC may playa role in formation of peroxynitrite that activates Nrf2 for GSTA2 induction and that PKC may serve an activator for GSTA2 induction downstream of PI3-kinase.