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은행잎에서 분리한 Polyphenol Oxidase의 정제 및 특성
설지연,박수선,김안근,Seol, Ji-Yeon,Park, Soo-Sun,Kim, An-Keun 한국생약학회 1999 생약학회지 Vol.30 No.3
Polyphenol Oxidase(PPO) was purified from an extract of Ginkgo biloba leaves by ammonium sulfate fractionation followed by sephadex G-150 column chromatography, which resulted in a 18-fold increase in specific activity. The enzyme was most active at pH 8.5 and the temperature optimum for the PPO catechol oxidation reaction was $45^{\circ}C$. Heat inactivation studies showed that heating for 7, 9 and 48 min, at 80, 70 and $60^{\circ}C$ respectively caused a 50% loss in enzymatic activity and that the enzyme was completely inactivated after heat treatment at $90^{\circ}C$ for 60 min. Km values of the PPO for catechol, hydroquinone and 4-methylcatechol derived from Lineweaver-Burk plots were $6.06\;{\times}\;10^{-4}M,\;1.02\;{\times}\;10^{-3}M,\;1.41\;{\times}\;10^{-3}M$ respectively. Of the substrates tested, 4-methylcatechol was oxidized most readily and the enzyme did not oxidize monophenols. The enzyme datalyzed browning reaction was completely inhibited in the presence of reducing reagents, namely ascorbic acid, cysteine, glutathione, 2-mercaptoethanol, potassium metabisulfite at 0.5 mM level. Sodium chloride showed very little inhibition effect on Ginkgo biloba leaves PPO. Lineweaver-Burk analysis of inhibition data revealed that the inhibition by cysteine, 2-mercaptoethanol, potassium cyanide was competitive with ki values of $1.1\;{\times}\;10^{-5}M,\;2.4\;{\times}\;10^{-5}M,\;8\;{\times}\;10^{-5}M$, respectively. Among the divalent cations, $Cu^{2+}ion$ was a strong activator on PPO and $Mn^{2+}ion$ was little or no effect on PPO activity $Ni^{2+}ion$ was an inhibitor on PPO.
Magnolia denudata에서 분리한 polyphenol oxidase의 정제 및 특성
김안근,설지연 숙명여자대학교 약학연구소 1996 약학논문집-숙명여자대학교 Vol.12 No.-
Polyphenol oxidase(PPO) was purfied from an extract of Magnolia denudata by ammonium sulfate precipitation, followed by sephadex G-150 column, which resulted in a 30.3-fold increase in specific activity. The purified preparation contained no monphenolase activity. The enzyme was most active at pH 6.0 and the temperature optimum for the PPO catechol oxidation reaction was 30℃. The enzyme was completely inactivated after heat treatment at 70℃ for 10min. Km values of the PPO for (+)-catechin, 4-methylcatechol, chlorogenic acid and dopamine derived from Lineweaver-Burk plots were 3.45×10^-3M, 1.25×10^-3M, 1.02×10^-3M, 1.96×10^-3M respectively. The enzyme more quickly oxidised (+)-catechin than other substrates used. Cysteine, glutathione, potassium metabisulfite and sodium diethyldithiocarbamate were potent inhibitors.
Tetrachloro[bis(2-chloroethyl) ethylenediamine-N,N] platinum(IV)가 소화요소 활성에 미치는 영향
김안근,이근임,설지연 숙명여자대학교 약학연구소 1993 약학논문집-숙명여자대학교 Vol.9 No.-
This study was carried out to know the effect of tetrachloro[bis (2-chloroethyl)ethylenedi amine-N,N'] plat inum(IV) (PtCl₄(2-CEen)) on a-amylase and pepsin activity. The comparison of PtCl₄(2-CEen) with cisplatin showed at each reaction. After the PtCl₄(2-CEen) reacted with a-amylase, its antitumor activity was examined. The effect of PtCl₄(2-CEen) on a-amylase activity showed inhibition. At high concentration relatively, it appears that the effect of inhibition was high. On the contrary, the effect of cisplatin on a-amylase activity showed activation. The relative activity was decreased, according as the concentration of cisplatin increases. The reaction mixture with PtCl₄(2-CEen) showed increased activity of pepsin than control. The activity of pepsin increased with increasing concentration of PtCl₄(2-CEen). On the contrary, cisplatin showed the inhibition of pepsin activity. The ratio of inhibition was decreased gradually, according as the concentration of cisplatin increases. After the PtCl₄(2-CEen) reacted with a-amylase, its antitumor activity was almost unchanged.
전골수성 백혈병 세포주 HL-60 에 대한 Doxorubicin 유발성 Apoptosis 와 Anti-Fas 항체 유발성 Apoptosis 의 비교
윤경식(Kyung Sik Yoon),설지연(Ji Yeon Seol),오현정(Hyun Jeong Ohh),이광수(Kwang Soo Lee),이원규(Won Kyu Lee),정성철(Sung Chul Jung) 한국응용약물학회 1999 Biomolecules & Therapeutics(구 응용약물학회지) Vol.7 No.1
Induction of apoptosis is considered to be the underlying mechanism that accounts for the efficiency of chemotherapeutic drugs. It has recently been proposed that doxorubicin (DOX) can induce apoptosis in human leukemic cells via the Fas/Fas Ligand (FasL) system. Comparison of Fas and Fast mRNA expression between drug- and anti-Fas antibody(Fas-Ab)- induced apoptosis was analyzed for examining the role of Fas/FasL system in the mediation of drug-induced apoptosis. After HL-60 cells were routinely cultured, MTT assay was performed for cytotoxicity test. Giemsa staining was carried out to monitor the apoptosis morphologically. By semiquantitative RT-PCR analysis, the expression of Fas and Fast at 4, 10, 24 hours was determined after DOX and Fas-Ab treatment. Dose-dependent cytotoxicity was induced by DOX-treatment, while Fas-Ab treatment showed the similar dose-dependent pattern but the cytotoxicity is not reached at LD_(50) at 100 ng/ml concentration of Fas-Ab. In the 10ng/ml DOX and 10ng/ml Fas-Ab treated group, typical apoptotic cell morphology was shown such as fragmented nuclei and cell membrane budding in the Giemsa-stained slide. Fas mRNA expression was not changed significantly in the both groups. But, FasL mRNA expression was induced significantly at initial period of apoptosis. In this study, Fas/FasL interaction assumed to be involved in drug-induced apoptosis.