Inhibitors of Tripeptidyl Peptidase II. 3. Derivation of Butabindide by Successive Structure Optimizations Leading to a Potential General Approach to Designing Exopeptidase Inhibitors
作者:C. Robin Ganellin、Paul B. Bishop、Ramesh B. Bambal、Suzanne M. T. Chan、Bertrand Leblond、Andrew N. J. Moore、Lihua Zhao、Pierre Bourgeat、Christiane Rose、Froylan Vargas、Jean-Charles Schwartz
DOI:10.1021/jm0500830
日期:2005.11.1
The cholecystokinin-8 (CCK-8)-inactivating peptidase is a serine peptidase that has been shown to be a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.14.10). It cleaves the neurotransmitter CCK-8 sulfate at the Met-Gly bond to give Asp-Tyr(SO(3)H)-Met-OH + GlyTrp-Met-Asp-Phe-NH(2). Starting from Val-Pro-NHBu, a dipeptide of submicromolar affinity that had previously been generated to serve as a lead, successive optimization at P3, P1, and then P2 gave Abu-Pro-NHBu (18, K(i) = 80 nM). Further transformation (by making a benzologue) gave the indoline analogue, butabindide (33) as a reversible inhibitor having nanomolar affinity (Ki = 7 nM). Retrospective analysis suggested the possibility of a general approach to designing exopeptidase inhibitors starting from the structure of the first hydrolysis product. Application of this approach to CCK-8 led to Abu-Phe-NHBu (37), but this only had K(i) = 9.4 mu M. Molecular modeling, to determine the minimum energy conformations and explain the 1000-fold better affinity of butabindide, indicated that 37 cannot access the likely active conformation of butabindide.