A method is presented for the preparation and use of fluorogenic peptide substrates that allows for the configuration of general substrate libraries to rapidly identify the primary and extended specificity of enzymes, such as proteases. The substrates contain a fluorogenic-leaving group, such as 7-amino-4-carbamoylmethyl-coumarin (ACC). Substrates incorporating the ACC leaving group show comparable kinetic profiles as those with the traditionally used 7-amino-4-methyl-coumarin (AMC) leaving group. The bifunctional nature of ACC allows for the efficient production of single substrates and substrate libraries using solid-phase synthesis techniques. The approximately 3-fold increased quantum yield of ACC over AMC permits reduction in enzyme and substrate concentrations. As a consequence, a greater number of substrates can be tolerated in a single assay, thus enabling an increase in the diversity space of the library. Soluble positional protease substrate libraries of 137,180 and 6,859 members, possessing amino acid diversity at the P4-P3-P2-P1 and P4-P3-P2 positions, respectively, were constructed. Employing this screening method the substrate specificities of a diverse array of proteases were profiled, including the serine proteases thrombin, plasmin, factor Xa, uPA, tPA, granzyme B, trypsin, chymotrypsin, human neutrophil elastase, and the cysteine proteases papain and cruzain. The resulting profiles create a pharmacophoric portrayal of the proteases allowing for the design of selective substrates and potent inhibitors.
本文介绍了一种制备和使用荧光肽底物的方法,可以配置通用底物库,快速确定酶(如
蛋白酶)的主要和扩展特异性。底物含有荧光离开基,如7-
氨基-4-羧甲基
香豆素(ACC)。含有ACC离开基的底物显示出与传统使用的7-
氨基-4-甲基
香豆素(
AMC)离开基相似的动力学特性。ACC的双功能性允许使用固相合成技术高效地生产单个底物和底物库。 ACC比
AMC的量子产率约高3倍,可以减少酶和底物浓度。因此,单个试验中可以容纳更多的底物,从而增加库的多样性空间。构建了137,180和6,859个可溶性定位
蛋白酶底物库,分别在P4-P3-P2-P1和P4-P3-P2位置具有
氨基酸多样性。利用这种筛选方法,对多种
蛋白酶的底物特异性进行了分析,包括
丝氨酸蛋白酶凝血酶、纤溶酶、Xa因子、uPA、tPA、颗粒酶B、胰
蛋白酶、胰凝乳
蛋白酶、人类中性粒细胞
弹性蛋白酶和半胱
氨酸
蛋白酶木瓜蛋白酶和克鲁赛因。所得到的特异性分析结果描绘了
蛋白酶的药效学特征,可以设计选择性底物和有效的
抑制剂。