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作 者 ：杨子明,杨秀芬

期 刊 ：中国中药杂志 2011年 36卷 17期 页码：2413.

关键词：三七总皂苷；谷胱甘肽转移-S-酶；酶动力学；半数抑制浓度；米氏常数；抑制常数；小鼠；

Keywords:total saponins of Panax notoginseng (PNS), glutathione-S-transferase, enzyme kinetics, IC50, Km, KI, mice,

摘 要 ：目的: 研究三七总皂苷(total saponins of Panax notoginseng,PNS)对小鼠肝脏谷胱甘肽-S-转移酶 (glutathione-S-transferase,GST) 的抑制作用及其酶动力学。 方法 :采用差速离心法制备小鼠胞质液酶,用半数效量概率单位法及Lineweaver-Burk双倒数作图法求得小鼠肝脏GST的米氏常数(K_m)、最大反应速度(V_max)和三七总皂苷对小鼠肝脏GST 的半数抑制浓度(IC₅₀)以及判断三七总皂苷对GST的抑制类型和抑制常数(KI,KIS)。 结果 : 三七总皂苷对小鼠肝脏GST有抑制作用,其IC₅₀是189.54 mg·L^-1;对底物还原型谷胱甘肽(GSH),GST的K_m是0.456 3 mmol·L^-1,V_max是476.19 U·mg^-1;对底物1-氯-2,4-二硝基苯(CDNB),GST的K_m是0.109 7 mmol·L^-1,V_max是400.00 U·mg^-1。对底物GSH,三七总皂苷对小鼠肝脏GST属于混合性抑制,其抑制常数KI是0.27 mg·L^-1,KIS是0.68 mg·L^-1;对底物CDNB,三七总皂苷对小鼠肝脏GST属于混合性抑制,其抑制常数KI是0.21 mg·L^-1,KIS是0.66 mg·L^-1。 结论 :三七总皂苷对小鼠肝脏GST的活性有明显抑制作用。

Abstract:Objective : To study the inhibition of glutathione-s-transferase by total saponins of Panax notoginseng and its kinetics analysis in liver of mice. Method : Mouse liver cytochyma enzyme was obtained by different velocity centrifugation, the mouse liver glutathione-S-transferase of michaelis constant (K_m), maximum velocity (V_max ) and the inhibition of glutathione-S-transferase by total saponins of P. notoginseng of 50% inhibiting concentration (IC₅₀), inhibition constant (KI, KIS), the type of inhibition were calculation by Lineweaver-Burk and the low of semi-effect-probit . Result : It was found that total saponins of P. notoginseng inhibited the glutathione-S-transferase activity with IC₅₀ of 189.54 mg·L^-1 . Kinetics analysis showed the glutathione-S-transferase of K_m was 0.456 3 mmol·L^-1 and V_max was 476.19 U·mg^-1 with reduced glutathione (GSH) substrate, 0.109 7 mmol·L^-1 (K_m) and 400.00 U·mg^-1 (V_max) with 1-chloro-2,4-dinitrobenzene (CDNB) substrate . Kinetics studies of total saponins of P. notoginseng on glutathione-S-transferase showed the inhibition were belong to mix-type with GSH and CDNB; the inhibition constant was 0.27 mg·L^-1 (KI), 0.68 mg·L^-1 (KIS) with GSH, and 0.21 mg·L^-1 (KI), 0.66 mg·L^-1 (KIS) with CDNB . Conclusion: Total saponins of P. notoginseng strongly inhibited the glutathione-S-transferase activity.

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