Irreversible inhibitors of cholesterol esterase

胰胆固醇酯酶（CE）在膳食胆固醇的吸收中具有双重功能。首先，CE催化胆固醇酯的水解以释放胆固醇用于吸收;其次，CE将胆固醇从胶束转运到肠上皮细胞的表面，在那里发生吸收。还有证据表明，CE在肠上皮细胞内的功能是在导致乳糜微粒形成的途径中重新溶解胆固醇。我们的假设是，抑制CE的任何这些功能将提供一种新的方法来治疗高胆固醇血症，通过限制膳食胆固醇的生物利用度。该提案将集中于开发用于防止胆固醇酯水解的CE的不可逆抑制剂。CE是一种丝氨酸酯酶，其催化机制与丝氨酸蛋白酶相似。我们建议开发选择性的不可逆抑制剂CE。我们的具体目标是：（1）开发用于合成卤烯醇内酯的通用方案，例如取代的6-氯吡喃酮作为胆固醇酯酶的潜在不可逆抑制剂，和（2）使用分子建模和动力学研究来减少CE的选择性抑制剂的开发的结构-活性关系。我们的初步工作表明，我们已经开发的合成方案的多功能性。将通过筛选化合物的CE灭活率（与胰凝乳蛋白酶、胰蛋白酶和弹性蛋白酶（均为在肠道内发挥功能的丝氨酸蛋白酶）相比），在酶水平确定选择性。

Pancreatic cholesterol esterase (CE) has a dual function in the absorption of dietary cholesterol. First, CE catalyzes the hydrolysis of cholesterol esters to liberate cholesterol for absorption; second, CE transports cholesterol from micelles to the surface of the enterocyte where absorption takes place. There is also evidence that CE functions within the enterocyte to re-esterify cholesterol in the pathway leading to the formation of chylomicrons. It is our hypothesis that inhibition of any of these functions of CE would provide a new approach to the treatment of hypercholesterolemia through limiting the bioavailability of dietary cholesterol. This proposal will focus on the development of irreversible inhibitors of CE for prevention of the hydrolysis of cholesterol ester. CE is a serine esterase with a catalytic mechanism that is similar to that of serine proteases. We propose to develop selective irreversible inhibitors of CE. Our specific aims are: (1) to develop versatile schemes for the synthesis of haloenol lactones such as substituted 6-chloropyrones as potential irreversible inhibitors of cholesterol esterase, and (2) to use molecular modeling and kinetic studies to reduce structure-activity relationships for the development of selective inhibitors of CE. Our preliminary work demonstrates the versatility of the synthetic schemes that we have developed. Selectivity will be determined at the enzyme level by screening compounds for their rates of inactivation of CE compared with the proteases chymotrypsin, trypsin and elastase, all of which are serine proteases that function within the intestine.