• 약학회지
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• 제38권3호
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• pp.351-357
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• 1994

The levels of maternal immunity enhancing factor(MIEF), which is an immunomodulatory protein identified from bovine colostrum, were determined by indirect competitive enzyme-linked immunosorbent assay(ELISA) for the colostrum and normal milk collected during the first two weeks of lactation. The mean concentration of MIEF in the colostrum of the first day of lactation was $109\;{\mu}g/ml$, and fell from the third day of lactation to $3{\sim}4\;{\mu}g/ml$. The molecular weight of the purified MIEF determined by reducing SDS-PAGE and TSK G2000SW column chromatography was 22,000 and 24,000 daltons, respectively, showing that MIEF is a monomeric peptide in its native form. To examine the capacity of MIEF to induce differentiation of B Lymphocytes, human tonsillar Iymphocytes were cultured in the presence of different concentrations of MIEF, and then antibody secreting cells were enumerated by enzyme-linked immunospot(ELISPOT) assay. When added to cultures of human tonsillar Lymphocytes, MIEF induced differentiation of resting B Iymphocyte to antibody secreting plasma cells as efficiently as LPS.

• 한국환경성돌연변이발암원학회지
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• 제25권3호
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• pp.97-103
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• 2005

The genotoxic effect of antimalarial drugs amodiaquine (AQ), mefloquine (MQ) and halofantrine (HF) was investigated in.at liver cells using the alkaline comet assay. AQ, MQ and HF at concentrations between $0-1000{\mu}mol/L$ significantly increased DNA strand breaks of rat liver cells dose-dependently. The order of induction of strand breaks was AQ>MQ>HF. The rat liver cells exposed to AQ and HF (200 and 400 ${\mu}mol/L$) and treated with (Fpg) the bacterial DNA repair enzyme that recognizes oxidized purine showed greater DNA damage than those not treated with the enzyme, providing evidence that AQ and HF induced oxidation of purines. Such an effect was not observed when MQ was treated with the enzyme. Treatment of cells with catalase, an enzyme inactivating hydrogen peroxide, decreased significantly the extent of DNA damage induced by AQ, and HF but not the one induced by MQ. Similarly quercetin, an antioxidant flavonoid at $50{\mu}mol/L$ attenuated the extent of the formation of DNA strand breaks by both AQ and HE. Quercetin, however, did not modify the effects of MQ. These results indicate the genotoxicity of AQ, MQ and HF in rat liver cells. In addition, the results suggest that reactive oxygen species may be involved in the formation of DNA lesions induced by AQ and HF and that, free radical scavengers may elicit protective effects against genotoxicity of these antimalarial drugs.

• Journal of Microbiology and Biotechnology
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• 제13권2호
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• pp.230-235
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• 2003

A 1.25 kb DNA fragment including the lscR gene, which encodes a levansucrase of Rahnella aquatilis ATCC 15552, was subcloned into a high-expression vector, pET-29b, and the recombinant enzyme was overexpressed in Escherichia coli. Most of the levansucrase activity was detected in the cytoplasmic fraction after induction with isopropyl ${\beta}-D-thiogalactoside$. The recombinant enzyme with a tag of six histidine residues at the C-terminus was purified 146-fold by affinity and gel-filtration chromatographies. The molecular mass of the purified LscR was approx. 49 kDa as determined by SDS-PAGE. The optimum pH and temperature of this enzyme for levan formation was pH 6.0 and $30^{\circ}C$, respectively. The optimum substrate concentration for levan formation was 300 mM sucrose. Levan formation was increased by the increase of the enzyme concentrations. Maxium yield of levan formation at optimum substrate concentration, pH, and temperature after 24 h of reaction was approximately 80%.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.344-349
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• 2004

A gene encoding inulin-degrading enzyme of Bacillus sp. snu-7 with ORF of 1536 nucleotides was cloned. And it was overexpressed as His-tagged protein in E. coli BL21(DE3) pLysS using pRSET B vector containing mature enzyme sequence. Maximum enzyme production was achieved by IPTG (0.1 mM) induction at $OD_{600}$ 1.2 and $30^{\circ}C$ followed by 6 h incubation. The expressed protein purified through immobilized metal affinity chromatography showed molecular mass of 60 kDa on SDS-PAGE. Results of thin-layer chromatography using inulin as a substrate showed the enzyme to be an exotype inulinase capable of producing only monomeric fructose as a product. $K_m$ and $k_{cat}$, for the hydrolyses of inulin and sucrose were $2.28\pm0.08$ mM and 358.05$\pm$20.38 $min^{-l}$, and 22.02$\pm$0.41 mM and 4619.11$\pm$215.12 $$min^{-1}, respectively. Optimal activity of the exoinulinase occurred at pH 7.0 and $50^{\circ}C$.

• Journal of Plant Biology
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• 제21권1_4호
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• pp.13-21
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• 1978

The effect of cyclic-AMP on the induction of acid phosphatase activity in barley aleurone layers was examined. Tannic acid was used as a inhibitor. Decursinol and coumarin were also used as a comparison. Maxiumu promotion of the enzyme activity was obtained with 10-5M cyclic-AMP, but this promotion was lower than that of 10-5M GAS induced enzyme activity in incubation medium. The inhibition rate in the addition of tannic acid was shown 17% and 63% at a ratio to GAs (by weight) of 10 : 1, and 58% and 94% at a ratio of 100 : 1 treated with GAs, and cyclic-AMP, respectively. The most potentiation of 10-6M GAS effect was induced by the additiion of suboptimal concentration (10-6M) of cyclic-AMP. Additional GAs and cyclic-AMP were shown the recovery of the enzyme activity inhibited by tannic acid. The combination with cyclic-AMP and theophylline enhanced the enzyme activity, too. Any other nucleotides tested except cyclic-AMP didn't show the action. There were no differences in acid phosphatase isozyme patterns by polyacrylamide disc electrophoresis, in conjunction with the different additions but the size of bands showed great differences. Especially, the 3rd band and the 5th band group were remarkable.

• 약학회지
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• 제37권1호
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• pp.41-48
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• 1993

The effect of captopril on the lung angiotensin converting enzyme (ACE) was investigated after 3 weeks oral administration (120~160 mg/kg/day) through drinking water in SpragueDawley rats. On the $^{125}$I-351A, an ACE inhibitor, binding assay in the isolated perpused lungs, the number of ACE molecules at the intrapulmonary endothelial cell surface was significantly decreased (p<0.001), and recovered to the normal level 7 days after discontinuation of captopril treatment. Intrapulmonary conversion ratio of Al to All was also significantly decreased (p<0.05) in the isolated perpused lungs. Bolus intravenous injection of angiotensin I did not showed pressor response in the both of systemic and pulmonary blood pressure of the anesthetized rats. ACE activity of the lung homogenates was also significantly reduced. These data consistently indicate the decrease of functionally active ACE molecule at the pulmonary artery after chronic captopril treatment. However, serum ACE activity was increased three fold in captopril treated rats compared to the normal rats. So, these results suggest that the functionally active ACE molecule at the pulmonary artery was still inhibited, which is directly associated with the antihypertensive effects, even if the total angiotensn converting enzyme induction was resulted after chronic captopril treatment.

• 동의생리병리학회지
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• 제20권6호
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• pp.1572-1575
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• 2006

Water extract from Cnidii Rhizoma (CRW) was tested for colon cancer chemopreventive activity by measuring the induction of phase II detoxification enzyme activity [quinone reductase (QR) and glutathione S-transferase (GST)] and glutathion (GSH) levels and ornithine decarboxylase (ODC) activity in cultured human colorectal adenocarcinoma HT-29 cells. CRW inhibited cell proliferation in cultured HT-29 cells. CRW induced QR activity in a dose-dependent manner in a concentration range of 0.1${\sim}$5.0 $mg/m{\ell}$. GST activity was also induced with the treatment of CRW in HT-29 cells. In addition GSH levels was increased with CRW. CRW inhibited ODC activity, a key enzyme of polyamine biosynthesis, which is enhanced in tumor promotion. These results suggest that CRW has colon cancer chemopreventive activity by increasing phase II enzyme activity and GSH levels and inhibiting ODC activity in vitro.

• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1559-1566
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• 2020

Compound K (C-K) is one of the most pharmaceutically effective ginsenosides, but it is absent in natural ginseng. However, C-K can be obtained through the hydrolysis of protopanaxadiol-type ginsenosides (PPDGs) in natural ginseng. The aim of this study was to obtain the high concentration of food-available C-K using PPDGs in Korean ginseng extract by an extracellular enzyme from Aspergillus niger KACC 46495. A. niger was cultivated in the culture medium containing the inducer carboxymethyl cellulose (CMC) for 6 days. The extracellular enzyme extracted from A. niger was prepared from the culture broth by filtration, ammonium sulfate, and dialysis. The extracellular enzyme was used for C-K production using PPDGs. The glycoside-hydrolyzing pathways for converting PPDGs into C-K by the extracellular enzyme were Rb1 → Rd → F2 → C-K, Rb2 → Rd or compound O → F2 or compound Y → C-K, and Rc → Rd or compound Mc1 → F2 or compound Mc → C-K. The extracellular enzyme from A. niger at 8.0 mg/ml, which was obtained by the induction of CMC during the cultivation, converted 6.0 mg/ml (5.6 mM) PPDGs in Korean ginseng extract into 2.8 mg/ml (4.5 mM) food-available C-K in 9 h, with a productivity of 313 mg/l/h and a molar conversion of 80%. To the best of our knowledge, the productivity and concentration of C-K of the extracellular enzyme are the highest among those by crude enzymes from wild-type microorganisms.

• Journal of Microbiology
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• 제45권4호
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• pp.333-338
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• 2007

Intracellular NADH:quinone reductase involved in degradation of aromatic compounds including lignin was purified and characterized from white rot fungus Trametes versicolor. The activity of quinone reductase was maximal after 3 days of incubation in fungal culture, and the enzyme was purified to homogeneity using ion-exchange, hydrophobic interaction, and gel filtration chromatographies. The purified enzyme has a molecular mass of 41kDa as determined by SDS-PAGE, and exhibits a broad temperature optimum between $20-40^{\circ}C$, with a pH optimum of 6.0. The enzyme preferred FAD as a cofactor and NADH rather than NADPH as an electron donor. Among quinone compounds tested as substrate, menadione showed the highest enzyme activity followed by 1,4-benzoquinone. The enzyme activity was inhibited by $CuSO_4,\;HgCl_2,\;MgSO_4,\;MnSO_4,\;AgNO_3$, dicumarol, KCN, $NaN_3$, and EDTA. Its $K_m\;and\;V_{max}$ with NADH as an electron donor were $23{\mu}M\;and\;101mM/mg$ per min, respectively, and showed a high substrate affinity. Purified quinone reductase could reduce 1,4-benzoquinone to hydroquinone, and induction of this enzyme was higher by 1,4-benzoquinone than those of other quinone compounds.

• 한국약용작물학회지
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• 제15권6호
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• pp.437-443
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• 2007

홍삼의 물추출물을 장기간 흰쥐에 급여했을 때 흰쥐 간의 이물질대사효소 활성도 유도에 미치는 영향을 조사하였다. 홍삼 물추출물의 급여농도는 25 mg/kg body weight이었으며, 간의 이물질대사효소 유도제는 항경련제 PB (80 mg/kg)와 발암제 3-MC (20 mg/kg)을 사용하였다. 간에서 이물질대사에 관여하는 cytochrome P-450의 함량, cytochrome P-450 dependent monooxygenase인 ECOD와 BPDM, cytochrome P-450 reductase와 GST의 활성도는 PB와 3-MC 투여에 의해서 대조군과 홍삼투여군 모두 크게 증가되었다. 흰쥐의 나이가 3개월에서는 두 유도제를 투여했을 때 이물질대사효소의 활성은 대조군이 인삼투여군에 비해 상대적으로 더 많이 유도되었다. 그러나 12개월에서는 두 시험군 모두 유도정도가 감소하였으나 홍삼투여군은 그 활성도 감소정도가 대조군에 비해 상대적으로 크지 않았다. 한편 두 그룹 모두 이물질대사 효소 중 cytochrome $B_5$ 함량과 cytochrome $b_5$ reductase의 활성도는 PB와 3-MC 투여에 의해서 뚜렷한 차이를 보이지 않았다. 따라서 이러한 결과는 흰쥐에 홍삼의 장기간 급여는 간에서 효소유도제의 이물질대사효소유도 정도를 조절하여 무독화에 기여할 수 있다는 것을 의미한다.