具有新型核心结构的肽类BACE1抑制剂的设计、合成及活性评价  

Synthesis and Activity of BACE1 Inhibitors with New Core Structure

作　　者：门秀峰[1] 何军林[1] 徐亮[1] 程军平[1] 周金武[1] 程肖蕊[1] 周文霞[1] 张永祥[1] 刘克良[1] 

机构地区：[1]军事医学科学院毒物药物研究所,北京100850

出　　处：《高等学校化学学报》2011年第2期316-321,共6页Chemical Journal of Chinese Universities

基　　金：国家"重大新药创制"科技重大专项基金(批准号:2009ZX09301-002和2009ZX09503-015)资助

摘　　要：BACE1(β-Site APP cleaving enzyme 1,β-secretase 1,Asp2,memapsin 2)抑制剂可能成为防治老年痴呆症的突破口之一,KMI-008是羟甲羰基(Hydroxymethylcarbonyl,HMC)类BACE1抑制剂中的先导化合物,其核心结构Pns(Phenylnorstatine)与BACE1的催化中心通过氢键和疏水作用,模拟了酶与底物形成的四面体过渡态,从而抑制BACE1.为寻找新结构的BACE1抑制剂,本研究以KMI-008为先导化合物,分别或同时引入4-羟基或氨基取代的脯氨酸及苯丙氨酸,筛选功能基的优势构象使其与酶形成氢键,并模拟Pns的疏水作用,进而模拟BACE1与底物形成的四面体过渡态,寻找新的核心结构.设计并合成了19条肽序列,用时间分辨荧光法测定目标肽体外对BACE1的抑制作用.所合成化合物对BACE1有一定的抑制作用,其中两个化合物LK-MX-41和LK-MX-42与先导化合物的活性相近,其核心结构由L-Phe-D-Pro组成,可以模拟BACE1的催化中心与底物相互作用的过渡态;含有该结构的肽序列,有望成为研究肽类BACE1抑制剂的另一途径.应用Autodock 4将所合成化合物与BACE1进行对接,结合体外活性测试结果,对构效关系进行了初步探讨.先导化合物及目标肽用固相法合成,经RP-HPLC测定纯度,ESI-MS确定分子量.BACE1（β-site APP cleaving enzyme 1,β-secretase 1,Asp2,memapsin 2） has been regarded as the key enzyme in the formation of amyloid-β protein,an etiological factor of Alzheimer＇s disease.Therefore,BACE1 inhibitors could be candidate drugs for the treatment of Alzheimer＇s disease.Among the multiple kinds of inhibitors,KMI-008 is a well-known lead compound in the series of compounds containing phenylnorstatine[（2R,3S）-3-amino-2-hydroxy-4-phenylbutyric acid,Pns],with a hydroxymethylcarbonyl（HMC） isostere as a transition-state mimic core strucuture,in which Pns is believed to be involved in several important interactions with the active site of BACE1,including hydrogen-bonding and hydrophobic interactions.In our research for new BACE1 inhibitors based on KMI-008,4-amino or hydroxyl-substituted proline（D/L） was introduced for a conformational selection for the functional group localization as well as hydrogen-bonding;Phe（D/L） was introduced for the hydrophobic interactions.Nineteen peptides were synthesized by solid phase synthesis and characterized with ESI-MS.Among various combinations of these two amino acid residues,L-Phe-D-Pro was proved to be the most effective core structure,two peptides（LK-MX-41 and LK-MX-42） with this core structure exhibited similar inhibitory activity as KMI-008.A primary structure-activity relationship and computer-aided docking results of the effective compounds with BACE1 were discussed.It seemed that L-Phe-D-Pro could be an alternative core structure in the design of new BACE1 inhibitors.

关 键 词：老年痴呆症 BACE1抑制剂 肽 脯氨酸 

分 类 号：O629.7[理学—有机化学]