The design and in vitro biochemical evaluation of two novel classes of mechanism-based inhibitors of human leukocyte elastase (HLE) that inactivate the enzyme via an unprecedented enzyme-induced sulfonamide fragmentation cascade is described. The inhibitors incorporate in their structure either an appropriately-functionalized saccharin scaffold, or a 1,2, 5-thiadiazolidin-3-one-1,1-dioxide scaffold. The inactivation of the enzyme by these inhibitors was found to be efficient, time-dependent and to involve the active site. Biochemical, HPLC, and mass spectrometric studies show that the interaction of these inhibitors with HLE results in the initial formation of a Michaelis-Menten complex and subsequent formation of a tetrahedral intermediate with the active site serine (Ser-195). Collapse of the tetrahedral intermediate with tandem fragmentation results in the formation of a highly reactive conjugated sulfonyl imine which can either react with water to form a relatively stable acyl enzyme and/or undergo a Michael addition reaction with an active site nucleophilic residue (His-57). The results also demonstrate convincingly the superiority of the 1, 2, 5-thiadiazolidin-3-one-1,1-dioxide scaffold over the saccharin scaffold in the design of inhibitors of (chymo)trypsin-like serine proteases. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry. / "December 2005."
| Identifer | oai:union.ndltd.org:WICHITA/oai:soar.wichita.edu:10057/763 |
| Date | 12 1900 |
| Creators | Gan, Xiangdong |
| Contributors | Groutas, William C. |
| Source Sets | Wichita State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Format | 494395 bytes, application/pdf |
| Rights | Copyright Xiangdong Gan, 2005. All rights reserved. |
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