Lyon Robert P, Hill John J, Atkins William M
Department of Medicinal Chemistry, Box 357610, University of Washington, Seattle, Washington 98195-7610, USA.
Biochemistry. 2003 Sep 9;42(35):10418-28. doi: 10.1021/bi0346188.
Exploiting the principle of bivalent binding, we have designed symmetrical, bifunctional inhibitors to simultaneously occupy both active sites of cytosolic glutathione S-transferase, with enhanced specificity for the P1-1 isoform. We have prepared two series of compounds that differ in their binding domains-the first is a series of bis-glutathione conjugates, and the second is a series of compounds each possessing two equivalents of Uniblue A, an analogue of Cibacron Blue. For each series, a monofunctional reference compound was also prepared to determine the relative advantage of the bivalent inhibitors. Within each series, the most potent inhibitors exhibited IC(50) values 2 orders of magnitude lower than the relevant reference compounds. Moreover, within the bis-glutathionyl series, a 10-fold increase in selectivity was achieved for GST P1-1 over the A1-1 isoform. Isothermal titration calorimetry with a representative bis-glutathione conjugate and a monofunctional reference compound indicates that the bivalent inhibitor exhibits the expected increase in intrinsic affinity and decrease in stoichiometry relative to the monofunctional compound, supporting the overall design strategy.
利用二价结合原理，我们设计了对称的双功能抑制剂，以同时占据胞质谷胱甘肽S-转移酶的两个活性位点，并增强对P1-1同工型的特异性。我们制备了两个系列的化合物，它们的结合域不同——第一个是一系列双谷胱甘肽缀合物，第二个是一系列各自含有两个当量的尤尼蓝A（汽巴蓝类似物）的化合物。对于每个系列，还制备了单功能参考化合物以确定二价抑制剂的相对优势。在每个系列中，最有效的抑制剂的IC(50)值比相关参考化合物低2个数量级。此外，在双谷胱甘肽系列中，GST P1-1相对于A1-1同工型的选择性提高了10倍。用代表性的双谷胱甘肽缀合物和单功能参考化合物进行的等温滴定量热法表明，相对于单功能化合物，二价抑制剂表现出预期的内在亲和力增加和化学计量比降低，支持了整体设计策略。
