摘要
目的研究二氢杨梅素(dihydromyricetin,DMY)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肝胞质液酶,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(Km)、最大反应速度(Vmax)和DMY对小鼠肝脏GST的半数抑制浓度(IC50),判断DMY对GST的抑制类型和抑制常数(Ki)。结果 DMY对小鼠肝脏GST有抑制作用,其IC50是(121.14±13.66)μmol.L-1;对底物还原型谷胱甘肽(GSH),GST的Km是0.1460 mmol.L-1,Vmax是175.44 U.mg-1;对底物1-氯-2,4-二硝基苯(CDNB),GST的Km是0.0937 mmol.L-1,Vmax是212.77 U.mg-1。对底物GSH,DMY对小鼠肝脏GST属于竞争性抑制,其抑制常数0.22 mmol.L-1;对底物CD-NB,DMY对小鼠肝脏GST属于非竞争性抑制,其抑制常数0.54 mmol.L-1。结论 DMY对小鼠肝脏GST的活性有明显抑制作用。
Aim To study the inhibition of glutathione-S-transferase by dihydromyricetin and its kinetics analysis in liver of mice.Methods Mouse liver cytochyma enzyme was obtained by different velocity centrifugation,the mouse liver glutathione-S-transferase of michaelis constant（Km）,maximum velocity（Vmax）and the inhibition of glutathione-S-transferase by dihydromyricetin of 50% inhibiting concentration（IC50）,inhibition constant（Ki）,the type of inhibition were calculated by Lineweaver-Burk and the low of semi-effect-probit.Results It was found that dihydromyricetin inhibited the glutathione-S-transferase activity with an IC50 of（121.14±13.66）μmol·L-1.Kinetics analysis showed the Km was 0.1460 mmol·L-1 and Vmax was 175.44 U·mg-1 for reduced glutathione（GSH）substrate and 0.0937 mmol·L-1（Km）and 212.77 U·mg-1（Vmax）for 1-chloro-2,4,-dinitrobenzene（CDNB）substrate.Kinetics studies of dihydromyricetin on glutathione-S-transferase showed the inhibition was competitive with GSH and noncompetitive with CDNB,and the inhibition constant was 0.22 mmol·L-1 with GSH and 0.54 mmol·L^1 with CDNB.Conclusion Dihydromyricetin can inhibit the glutathione-S-transferase activity in liver of mice.
出处
《中国药理学通报》
CAS
CSCD
北大核心
2010年第7期894-898,共5页
Chinese Pharmacological Bulletin
基金
国家自然科学基金资助项目(No30660228)
广西高等学校优秀人才资助计划资助项目(No桂RC2007016)
