Two alkaloids as α-amylase inhibitors: enzyme kinetics and molecular modeling investigations  

两种生物碱抑制剂:α-淀粉酶的动力学及分子模拟研究(英文)

作　　者：梁毅[1] 裴芬[2] 王弘[1] 陈世忠[1] 

机构地区：[1]北京大学医学部药学院天然药物化学系,北京100191 [2]北京大学医学部药学院天然药物及仿生药物国家重点实验室,北京100191

出　　处：《Journal of Chinese Pharmaceutical Sciences》2015年第2期80-87,共8页中国药学（英文版）

基　　金：State Key Laboratory of Natural and Biomimetic Drugs 2013 Funded Project "Establishment and Application an Online Natural Medicines System with Efficient Separation,Structural Identification and Activity Detection"

摘　　要：In the present study, we studied the inhibitory effects of chelidonine and rutaecarpin on porcine pancreatic a-amylase （PPA） catalyzed hydrolysis using 2-chloro-4-nitrophenyl-4-O-β-D-galactopyranosylmaltoside （Gal-G2-α-CNP）. We, for the first time, provided kinetic report and detailed inhibitory effects of both compounds on PPA. Lineweaver-Burk plot revealed that the inhibition was a mixed-noncompetitive type, and only one molecule of inhibitor bound to the enzyme or to the enzyme-substrate complex. Kinetic constants calculated from secondary plots were in millimole range. Dissociation constants of enzyme-inhibitor complex （KEI） were 0.9 mM and 3.5 mM, respectively. Moreover, dissociation constants of enzyme-inhibitor-substrate complex （KESI） were 0.04 mM and 0.31 mM, respectively. These data indicated that the inhibition was more inclined to competitive to Gal-G2-α-CNP hydrolysis. Further molecular docking study manifested that hydrogen bonding formed between acarbose and aspartic acid （Asp300）, histidine （His305） and glycine （Gly3-6）, while hydrogen bonding was observed between chelidonine and glutamic acid （Glu233）, lysine （Lys200） and His305. In addition, rutaecarpine had only one hydrogen bond with Lys200. Our data indicated that chelidonine and rutaecarpine were two promising drug candidates, and chelidonine possessed stronger inhibitory effect compared with rutaecarpine.用2-氯-4-硝基-α-半乳糖麦芽糖苷(Gal-G2-α-CNP)作底物研究猪胰腺淀粉酶抑制剂:白屈菜碱和吴茱萸次碱的抑制效力。首次报道白屈菜碱和吴茱萸次碱抑制淀粉酶的活性,并用动力学方法研究其抑制猪胰腺淀粉酶的抑制剂的类型。结果表明在使用Gal-G2-α-CNP作为底物时,两种抑制剂均为混合非竞争型抑制剂,且一分子的抑制剂只与一分子的酶结合。用二次作图计算的动力学常数分别为:白屈菜碱,K EI:0.9 m M,K ESI:0.04 m M;吴茱萸次碱,K EI:3.5 m M,K ESI:0.31 m M。这说明白屈菜碱和吴茱萸次碱更倾向于竞争型抑制剂。用GOLD软件进行分子对接,结果显示,阿卡波糖与Glu233,Lys200和His305氨基酸残基有氢键作用,而白屈菜碱与Glu233,Lys200和His305有氢键作用,吴茱萸次碱只与Lys200有氢键作用。研究结果表明白屈菜碱和吴茱萸次碱作为淀粉酶抑制剂应用的前景良好,且白屈菜碱的抑制作用强于吴茱萸次碱。

关 键 词：α-Amylase inhibitors Kinetic analysis Molecular modeling Chelidonine RUTAECARPINE 

分 类 号：R96[医药卫生—药理学]